8.7

95 files changed, 2768 insertions, 1863 deletions

diff --git a/FreeFileSync/Build/Changelog.txt b/FreeFileSync/Build/Changelog.txt
index cf12e790..2831c26d 100644
--- a/FreeFileSync/Build/Changelog.txt
+++ b/FreeFileSync/Build/Changelog.txt
@@ -1,3 +1,20 @@
+FreeFileSync 8.7 [2016-12-06]
+-----------------------------
+New auto-updater feature for FreeFileSync Donation Edition
+Download zip archive of portable FreeFileSync Donation Edition
+New command line options to define parameters for silent installation
+Support offline activation for portable Donation Edition
+Use automatic keyboard-interactive SFTP authentication as fallback
+Check for available SFTP authentication methods before login
+Support cloud sync of portable edition installation files
+Access donation transaction details from about dialog
+Use width from flexible grid column when showing/hiding extra columns
+Show item short names in middle column tooltip
+Enhanced file category descriptions with modification times
+Don't warn about missing recycle bin when only moving or updating attributes
+Fixed crash when switching to main dialog during batch sync
+
+
 FreeFileSync 8.6 [2016-10-25]
 -----------------------------
 Added SFTP support for OS X
diff --git a/FreeFileSync/Build/Help/html/exclude-items.html b/FreeFileSync/Build/Help/html/exclude-items.html
index bc60d79a..6e3cf0d9 100644
--- a/FreeFileSync/Build/Help/html/exclude-items.html
+++ b/FreeFileSync/Build/Help/html/exclude-items.html
@@ -72,7 +72,7 @@
 	
 	<h2>Example: <span style="font-weight:normal">Exclude a sub folder except for certain files</span></h2>
 	<p>
-		Set up two folder pairs with the same source and target paths but with distinct local filters:<br>
+		Set up <b>two folder pairs</b> with the same source and target paths but with distinct local filters:<br>
 		Folder pair 1; local <em>exclude</em> filter: <span class="file-path">\SubFolder\</span><br>
 		Folder pair 2; local <em>include</em> filter: <span class="file-path">\SubFolder\*.txt</span>
 	</p>
diff --git a/FreeFileSync/Build/Languages/arabic.lng b/FreeFileSync/Build/Languages/arabic.lng
index 1d1bb221..1f735dae 100644
--- a/FreeFileSync/Build/Languages/arabic.lng
+++ b/FreeFileSync/Build/Languages/arabic.lng
@@ -115,9 +115,6 @@
 <source>Path to an alternate GlobalSettings.xml file.</source>
 <target>تحديد مسار مختلف لملف GlobalSettings.xml.</target>
 
-<source>Any number of FreeFileSync .ffs_gui and/or .ffs_batch configuration files.</source>
-<target>أي عدد من ملفات خيارات FreeFileSync أو\و _gui and/or .ffs_batch.</target>
-
 <source>Any number of alternative directory pairs for at most one config file.</source>
 <target>أي عدد من أزواج المسارات البديلة من أجل ملف خيارات واحد.</target>
 
@@ -278,8 +275,8 @@ Actual: %y bytes
 </source>
 <target>
 حجم غير متوقع لتدفق البيانات.
-المتوقع: %x bytes
-الفعلي: %y bytes
+المتوقع: ‎%x bytes
+الفعلي: ‎%y bytes
 </target>
 
 <source>Cannot copy symbolic link %x to %y.</source>
@@ -344,22 +341,22 @@ Actual: %y bytes
 <pluralform>%x bytes</pluralform>
 </source>
 <target>
-<pluralform>0 byte</pluralform>
-<pluralform>1 byte</pluralform>
-<pluralform>2 bytes</pluralform>
-<pluralform>%x bytes</pluralform>
-<pluralform>%x bytes</pluralform>
-<pluralform>%x bytes</pluralform>
+<pluralform>‎0 byte</pluralform>
+<pluralform>‎1 byte</pluralform>
+<pluralform>‎2 bytes</pluralform>
+<pluralform>‎%x bytes</pluralform>
+<pluralform>‎%x bytes</pluralform>
+<pluralform>‎%x bytes</pluralform>
 </target>
 
 <source>%x MB</source>
-<target>%x MB</target>
+<target>‎%x MB</target>
 
 <source>%x KB</source>
-<target>%x KB</target>
+<target>‎%x KB</target>
 
 <source>%x GB</source>
-<target>%x GB</target>
+<target>‎%x GB</target>
 
 <source>Cannot load file %x.</source>
 <target>لا يمكن فتح الملف  %x.</target>
@@ -900,9 +897,6 @@ The command is triggered if:
 <source>Find:</source>
 <target>بحث:</target>
 
-<source>Match case</source>
-<target>مطابقة حالة الأحرف (Match case)</target>
-
 <source>New</source>
 <target>جديد</target>
 
@@ -1212,7 +1206,7 @@ This guarantees a consistent state even in case of a serious error.
 <target>الا&فتراضي</target>
 
 <source>Source code written in C++ using:</source>
-<target>الرماز المصدري مكتوب بلغة C++ باستخدام:</target>
+<target>الرماز المصدري مكتوب بلغة C++‎ باستخدام:</target>
 
 <source>If you like FreeFileSync:</source>
 <target>إذا أعجبك FreeFileSync:</target>
@@ -1590,9 +1584,6 @@ This guarantees a consistent state even in case of a serious error.
 <source>Parent folder path</source>
 <target>مسار المجلد الحاوي</target>
 
-<source>Temporary local copy for SFTP and MTP storage</source>
-<target>نسخة محلية مؤقتة لتخزين SFTP and MTP</target>
-
 <source>Parameters for opposite side</source>
 <target>معلمات الجانب المعاكس</target>
 
@@ -1756,10 +1747,10 @@ This guarantees a consistent state even in case of a serious error.
 <target>نوع العنصر %x غير مدعوم:</target>
 
 <source>%x TB</source>
-<target>%x TB</target>
+<target>‎%x TB</target>
 
 <source>%x PB</source>
-<target>%x PB</target>
+<target>‎%x PB</target>
 
 <source>
 <pluralform>1 min</pluralform>
diff --git a/FreeFileSync/Build/Languages/english_uk.lng b/FreeFileSync/Build/Languages/english_uk.lng
index 6508fcb0..648076bf 100644
--- a/FreeFileSync/Build/Languages/english_uk.lng
+++ b/FreeFileSync/Build/Languages/english_uk.lng
@@ -1,5 +1,5 @@
 <header>
-	<language>English (UK)</language>
+	<language>English (UK)‎</language>
 	<translator>Robert Readman</translator>
 	<locale>English (U.K.)</locale>
 	<image>flag_england.png</image>
diff --git a/FreeFileSync/Build/Languages/german.lng b/FreeFileSync/Build/Languages/german.lng
index d6cc1e25..a3cff38c 100644
--- a/FreeFileSync/Build/Languages/german.lng
+++ b/FreeFileSync/Build/Languages/german.lng
@@ -7,6 +7,12 @@
 	<plural_definition>n == 1 ? 0 : 1</plural_definition>
 </header>
 
+<source>Installation was registered on a different operating system.</source>
+<target>Die Installation wurde auf einem anderen Betriebssystem registriert.</target>
+
+<source>The server does not support authentication via %x.</source>
+<target>Der Server unterstützt keine Authentifizierung über %x.</target>
+
 <source>Both sides have changed since last synchronization.</source>
 <target>Beide Seiten wurden seit der letzten Synchronisation verändert.</target>
 
@@ -130,14 +136,14 @@
 <source>Date:</source>
 <target>Datum:</target>
 
-<source>Files %x have the same date but a different size.</source>
-<target>Die Dateien %x haben dasselbe Datum, aber unterschiedliche Größen.</target>
+<source>Files have the same date but a different size.</source>
+<target>Die Dateien haben dasselbe Datum, aber unterschiedliche Größen.</target>
 
 <source>Size:</source>
 <target>Größe:</target>
 
-<source>Content comparison was skipped for excluded files %x.</source>
-<target>Der Vergleich nach Dateiinhalt wurde für die ausgeschlossenen Dateien %x übersprungen.</target>
+<source>Content comparison was skipped for excluded files.</source>
+<target>Der Vergleich nach Dateiinhalt wurde für die ausgeschlossenen Dateien übersprungen.</target>
 
 <source>Items differ in attributes only</source>
 <target>Die Elemente unterscheiden sich nur in Attributen</target>
@@ -279,8 +285,8 @@ Tatsächlich: %y bytes
 <source>Cannot open directory %x.</source>
 <target>Das Verzeichnis %x kann nicht geöffnet werden.</target>
 
-<source>Cannot enumerate directory %x.</source>
-<target>Das Verzeichnis %x kann nicht gelistet werden.</target>
+<source>Cannot read directory %x.</source>
+<target>Das Verzeichnis %x kann nicht gelesen werden.</target>
 
 <source>Cannot read file attributes of %x.</source>
 <target>Die Dateiattribute von %x können nicht gelesen werden.</target>
@@ -381,7 +387,7 @@ Tatsächlich: %y bytes
 <source>Database file %x does not yet exist.</source>
 <target>Die Datenbankdatei %x existiert noch nicht.</target>
 
-<source>Database file is corrupt:</source>
+<source>Database file is corrupted:</source>
 <target>Die Datenbankdatei ist beschädigt:</target>
 
 <source>Database files do not share a common session.</source>
@@ -863,11 +869,8 @@ Die Befehlszeile wird ausgelöst, wenn:
 <source>&Tools</source>
 <target>E&xtras</target>
 
-<source>&Check for new version</source>
-<target>&Auf neue Version prüfen</target>
-
-<source>&Check now</source>
-<target>&Jetzt prüfen</target>
+<source>&Check for updates now</source>
+<target>&Jetzt auf Aktualisierung prüfen</target>
 
 <source>Check &automatically once a week</source>
 <target>&Automatisch wöchentlich prüfen</target>
@@ -1240,6 +1243,9 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Source code written in C++ using:</source>
 <target>Der Quellcode wurde in C++ geschrieben mit:</target>
 
+<source>Donation details</source>
+<target>Spendendetails</target>
+
 <source>If you like FreeFileSync:</source>
 <target>Wenn Sie FreeFileSync mögen:</target>
 
@@ -1249,7 +1255,7 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Feedback and suggestions are welcome</source>
 <target>Feedback und Vorschläge sind willkommen</target>
 
-<source>Homepage</source>
+<source>Home page</source>
 <target>Homepage</target>
 
 <source>Email</source>
@@ -1261,6 +1267,27 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Many thanks for localization:</source>
 <target>Vielen Dank für die Lokalisation:</target>
 
+<source>Activate the FreeFileSync Donation Edition by one of the following methods:</source>
+<target>Aktivieren Sie die FreeFileSync Spendenversion durch eine der folgenden Methoden:</target>
+
+<source>1. Activate via internet now:</source>
+<target>1. Jetzt über das Internet aktivieren:</target>
+
+<source>Activate online</source>
+<target>Online aktivieren</target>
+
+<source>2. Retrieve an offline activation key from the following URL:</source>
+<target>2. Einen Offline-Aktivierungsschlüssel von folgender URL abrufen:</target>
+
+<source>&Copy to clipboard</source>
+<target>In &Zwischenablage kopieren</target>
+
+<source>Enter activation key:</source>
+<target>Aktivierungsschlüssel eingeben:</target>
+
+<source>Activate offline</source>
+<target>Offline aktivieren</target>
+
 <source>SSH File Transfer Protocol</source>
 <target>SSH File Transfer Protocol</target>
 
@@ -1279,6 +1306,9 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Select Time Span</source>
 <target>Zeitspanne auswählen</target>
 
+<source>FreeFileSync Donation Edition</source>
+<target>FreeFileSync Spendenversion</target>
+
 <source>&Options</source>
 <target>&Optionen</target>
 
@@ -1300,8 +1330,8 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Overview</source>
 <target>Übersicht</target>
 
-<source>&Download</source>
-<target>Zum &Download</target>
+<source>&Show details</source>
+<target>&Zeige Details</target>
 
 <source>A new version of FreeFileSync is available:</source>
 <target>Eine neue Version von FreeFileSync ist verfügbar:</target>
@@ -1543,6 +1573,12 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Loading...</source>
 <target>Lade...</target>
 
+<source>Installation files are corrupted. Please reinstall FreeFileSync.</source>
+<target>Die Installationsdateien sind beschädigt. Bitte installieren Sie FreeFileSync neu.</target>
+
+<source>Thank you, %x, for your donation and support!</source>
+<target>Danke %x für die Spende und Unterstützung!</target>
+
 <source>Password:</source>
 <target>Passwort:</target>
 
@@ -1606,6 +1642,9 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>&Show</source>
 <target>&Zeigen</target>
 
+<source>Downloading update...</source>
+<target>Lade Aktualisierung...</target>
+
 <source>Identify equal files by comparing modification time and size.</source>
 <target>Erkenne gleiche Dateien anhand der Änderungszeit und Größe.</target>
 
@@ -1699,12 +1738,33 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Percentage</source>
 <target>Prozent</target>
 
+<source>Failed to retrieve update information.</source>
+<target>Aktualisierungsinformationen konnten nicht abgerufen werden.</target>
+
+<source>Automatic updates:</source>
+<target>Automatische Aktualisierung:</target>
+
+<source>Requires FreeFileSync Donation Edition</source>
+<target>Benötigt FreeFileSync Spendenversion</target>
+
 <source>Check for Program Updates</source>
 <target>Suche nach neuer Programmversion</target>
 
+<source>Auto-update now or download manually from the FreeFileSync home page?</source>
+<target>Jetzt automatisch aktualisieren oder manuell von der FreeFileSync Homepage herunterladen?</target>
+
+<source>&Auto-update</source>
+<target>&Automatisch</target>
+
+<source>&Home page</source>
+<target>&Homepage</target>
+
 <source>Download now?</source>
 <target>Jetzt herunterladen?</target>
 
+<source>&Download</source>
+<target>Zum &Download</target>
+
 <source>FreeFileSync is up to date.</source>
 <target>FreeFileSync ist auf dem neuesten Stand.</target>
 
@@ -1717,14 +1777,17 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Consistency check failed for %x.</source>
 <target>Die Konsistenzprüfung für %x ist fehlgeschlagen.</target>
 
-<source>Cannot find system function %x.</source>
-<target>Die Systemfunktion %x wurde nicht gefunden.</target>
+<source>Failed to activate FreeFileSync Donation Edition.</source>
+<target>Die Aktivierung der FreeFileSync Spendenversion ist fehlgeschlagen.</target>
+
+<source>Incorrect activation key.</source>
+<target>Falscher Aktivierungsschlüssel.</target>
 
 <source>Unable to register to receive system messages.</source>
 <target>Die Registrierung zum Empfang von Systemmeldungen ist fehlgeschlagen.</target>
 
-<source>Installation files are corrupt. Please reinstall FreeFileSync.</source>
-<target>Die Installationsdateien sind beschädigt. Bitte installieren Sie FreeFileSync neu.</target>
+<source>Cannot find system function %x.</source>
+<target>Die Systemfunktion %x wurde nicht gefunden.</target>
 
 <source>Unable to register device notifications for %x.</source>
 <target>Die Registrierung für Gerätemeldungen ist für %x fehlgeschlagen.</target>
@@ -1882,15 +1945,6 @@ Dadurch wird ein konsistenter Datenstand auch bei schweren Fehlern garantiert.
 <source>Edit with FreeFileSync</source>
 <target>Mit FreeFileSync editieren</target>
 
-<source>Thank you, %x, for your donation and support!</source>
-<target>Danke %x für die Spende und Unterstützung!</target>
-
-<source>This FreeFileSync installer for donors has reached its daily installation limit.</source>
-<target>Das FreeFileSync Installationsprogramm für Spender hat sein tägliches Installationslimit erreicht.</target>
-
-<source>Download the regular version from the FreeFileSync homepage now?</source>
-<target>Jetzt die normale Version von der FreeFileSync Homepage herunterladen?</target>
-
 <source>The portable version cannot install into the selected folder.</source>
 <target>Die portable Version kann nicht in den gewählten Ordner installiert werden.</target>
 
diff --git a/FreeFileSync/Build/Languages/hebrew.lng b/FreeFileSync/Build/Languages/hebrew.lng
index 3fdd3083..48fc065d 100644
--- a/FreeFileSync/Build/Languages/hebrew.lng
+++ b/FreeFileSync/Build/Languages/hebrew.lng
@@ -1184,7 +1184,7 @@ This guarantees a consistent state even in case of a serious error.
 <target>&ברירת מחדל</target>
 
 <source>Source code written in C++ using:</source>
-<target>קוד מקור נכתב ב- C++ באמצעות:</target>
+<target>קוד מקור נכתב ב- C++‎ באמצעות:</target>
 
 <source>If you like FreeFileSync:</source>
 <target>במידה ו-FreeFileSync מוצאת חן בעינכם:</target>
diff --git a/FreeFileSync/Build/Languages/portuguese_br.lng b/FreeFileSync/Build/Languages/portuguese_br.lng
index b155f3a9..8a420222 100644
--- a/FreeFileSync/Build/Languages/portuguese_br.lng
+++ b/FreeFileSync/Build/Languages/portuguese_br.lng
@@ -1,5 +1,5 @@
 <header>
-	<language>Português (BR)</language>
+	<language>Português (BR)‎</language>
 	<translator>Edison Aranha</translator>
 	<locale>pt_BR</locale>
 	<image>flag_brazil.png</image>
diff --git a/FreeFileSync/Build/Languages/russian.lng b/FreeFileSync/Build/Languages/russian.lng
index 620d79bd..3933e8bb 100644
--- a/FreeFileSync/Build/Languages/russian.lng
+++ b/FreeFileSync/Build/Languages/russian.lng
@@ -796,7 +796,7 @@ The command is triggered if:
 <target>Выберите папку SFTP</target>
 
 <source>Select alternative folder type</source>
-<target>Выберете альтернативный тип папки</target>
+<target>Выберите альтернативный тип папки</target>
 
 <source>&New</source>
 <target>&Новая</target>
@@ -895,7 +895,7 @@ The command is triggered if:
 <target>Тип просмотра:</target>
 
 <source>Select view:</source>
-<target>Выберете отображение:</target>
+<target>Выберите отображение:</target>
 
 <source>Statistics:</source>
 <target>Статистика:</target>
@@ -1062,10 +1062,10 @@ The command is triggered if:
 <target>Папка на сервере:</target>
 
 <source>Select a directory on the server:</source>
-<target>Выберете папку на сервере:</target>
+<target>Выберите папку на сервере:</target>
 
 <source>Select Folder</source>
-<target>Выберете папку</target>
+<target>Выберите папку</target>
 
 <source>Start synchronization now?</source>
 <target>Начать синхронизацию сейчас?</target>
@@ -1098,7 +1098,7 @@ The command is triggered if:
 <target>Свернуть в область уведомлений</target>
 
 <source>Bytes copied:</source>
-<target>Данных скопированно:</target>
+<target>Данных скопировано:</target>
 
 <source>Close</source>
 <target>Закрыть</target>
diff --git a/FreeFileSync/Build/Languages/spanish.lng b/FreeFileSync/Build/Languages/spanish.lng
index 62240f19..aafbacec 100644
--- a/FreeFileSync/Build/Languages/spanish.lng
+++ b/FreeFileSync/Build/Languages/spanish.lng
@@ -1,6 +1,6 @@
 <header>
 	<language>Español</language>
-	<translator>I.R.Maturana (irmlab.com)</translator>
+	<translator>I.R.Maturana (irmlab.com)‎</translator>
 	<locale>es_ES</locale>
 	<image>flag_spain.png</image>
 	<plural_count>2</plural_count>
diff --git a/FreeFileSync/Build/Resources.zip b/FreeFileSync/Build/Resources.zip
index 9acc3a10..85b1967d 100644
--- a/FreeFileSync/Build/Resources.zip
+++ b/FreeFileSync/Build/Resources.zip
diff --git a/FreeFileSync/Source/RealTimeSync/application.cpp b/FreeFileSync/Source/RealTimeSync/application.cpp
index 735e0b8b..cc127249 100644
--- a/FreeFileSync/Source/RealTimeSync/application.cpp
+++ b/FreeFileSync/Source/RealTimeSync/application.cpp
@@ -65,7 +65,7 @@ bool Application::OnInit()
     wxToolTip::SetMaxWidth(-1); //disable tooltip wrapping -> Windows only
 
 #elif defined ZEN_LINUX
-    ::gtk_rc_parse((zen::getResourceDir() + "styles.gtk_rc").c_str()); //remove inner border from bitmap buttons
+    ::gtk_rc_parse((zen::getResourceDirPf() + "styles.gtk_rc").c_str()); //remove inner border from bitmap buttons
 #endif
 
     //Windows User Experience Interaction Guidelines: tool tips should have 5s timeout, info tips no timeout => compromise:
@@ -74,7 +74,18 @@ bool Application::OnInit()
 
     SetAppName(L"RealTimeSync");
 
-    initResourceImages(getResourceDir() + Zstr("Resources.zip"));
+    initResourceImages(getResourceDirPf() + Zstr("Resources.zip"));
+
+    try
+    {
+        setLanguage(xmlAccess::getProgramLanguage()); //throw FileError
+    }
+    catch (const FileError& e)
+    {
+        warn_static("Bug? (exit on frame delete)")
+        showNotificationDialog(nullptr, DialogInfoType::ERROR2, PopupDialogCfg().setDetailInstructions(e.toString()));
+        //continue!
+    }
 
     Connect(wxEVT_QUERY_END_SESSION, wxEventHandler(Application::onQueryEndSession), nullptr, this);
     Connect(wxEVT_END_SESSION,       wxEventHandler(Application::onQueryEndSession), nullptr, this);
@@ -85,7 +96,6 @@ bool Application::OnInit()
     Connect(EVENT_ENTER_EVENT_LOOP, wxEventHandler(Application::onEnterEventLoop), nullptr, this);
     wxCommandEvent scrollEvent(EVENT_ENTER_EVENT_LOOP);
     AddPendingEvent(scrollEvent);
-
     return true; //true: continue processing; false: exit immediately.
 }
 
@@ -103,17 +113,6 @@ void Application::onEnterEventLoop(wxEvent& event)
 {
     Disconnect(EVENT_ENTER_EVENT_LOOP, wxEventHandler(Application::onEnterEventLoop), nullptr, this);
 
-    try
-    {
-        wxLanguage lngId = xmlAccess::getProgramLanguage();
-        setLanguage(lngId); //throw FileError
-    }
-    catch (const FileError& e)
-    {
-        showNotificationDialog(nullptr, DialogInfoType::ERROR2, PopupDialogCfg().setDetailInstructions(e.toString()));
-        //continue!
-    }
-
     //try to set config/batch- filepath set by %1 parameter
     std::vector<Zstring> commandArgs;
     for (int i = 1; i < argc; ++i)
diff --git a/FreeFileSync/Source/RealTimeSync/main_dlg.cpp b/FreeFileSync/Source/RealTimeSync/main_dlg.cpp
index af22b7a0..4bb61add 100644
--- a/FreeFileSync/Source/RealTimeSync/main_dlg.cpp
+++ b/FreeFileSync/Source/RealTimeSync/main_dlg.cpp
@@ -73,7 +73,7 @@ void MainDialog::create(const Zstring& cfgFile)
 
 MainDialog::MainDialog(wxDialog* dlg, const Zstring& cfgFileName)
     : MainDlgGenerated(dlg),
-      lastRunConfigPath(zen::getConfigDir() + Zstr("LastRun.ffs_real"))
+      lastRunConfigPath_(zen::getConfigDirPathPf() + Zstr("LastRun.ffs_real"))
 {
 #ifdef ZEN_WIN
     new MouseMoveWindow(*this); //ownership passed to "this"
@@ -100,9 +100,9 @@ MainDialog::MainDialog(wxDialog* dlg, const Zstring& cfgFileName)
     //--------------------------- load config values ------------------------------------
     xmlAccess::XmlRealConfig newConfig;
 
-    const Zstring currentConfigFile = cfgFileName.empty() ? lastRunConfigPath : cfgFileName;
+    const Zstring currentConfigFile = cfgFileName.empty() ? lastRunConfigPath_ : cfgFileName;
     bool loadCfgSuccess = false;
-    if (!cfgFileName.empty() || fileExists(lastRunConfigPath))
+    if (!cfgFileName.empty() || fileExists(lastRunConfigPath_))
         try
         {
             std::wstring warningMsg;
@@ -161,7 +161,7 @@ MainDialog::~MainDialog()
 
     try //write config to XML
     {
-        writeConfig(currentCfg, lastRunConfigPath); //throw FileError
+        writeConfig(currentCfg, lastRunConfigPath_); //throw FileError
     }
     catch (const FileError& e)
     {
@@ -172,7 +172,7 @@ MainDialog::~MainDialog()
 
 void MainDialog::onQueryEndSession()
 {
-    try { writeConfig(getConfiguration(), lastRunConfigPath); } //throw FileError
+    try { writeConfig(getConfiguration(), lastRunConfigPath_); } //throw FileError
     catch (const FileError&) {} //we try our best do to something useful in this extreme situation - no reason to notify or even log errors here!
 }
 
@@ -228,7 +228,7 @@ void MainDialog::OnStart(wxCommandEvent& event)
 
     xmlAccess::XmlRealConfig currentCfg = getConfiguration();
 
-    switch (rts::startDirectoryMonitor(currentCfg, xmlAccess::extractJobName(utfCvrtTo<Zstring>(currentConfigFileName))))
+    switch (rts::startDirectoryMonitor(currentCfg, xmlAccess::extractJobName(utfCvrtTo<Zstring>(currentConfigFileName_))))
     {
         case rts::EXIT_APP:
             Close();
@@ -249,7 +249,7 @@ void MainDialog::OnStart(wxCommandEvent& event)
 
 void MainDialog::OnConfigSave(wxCommandEvent& event)
 {
-    Zstring defaultFileName = currentConfigFileName.empty() ? Zstr("Realtime.ffs_real") : currentConfigFileName;
+    Zstring defaultFileName = currentConfigFileName_.empty() ? Zstr("Realtime.ffs_real") : currentConfigFileName_;
     //attention: currentConfigFileName may be an imported *.ffs_batch file! We don't want to overwrite it with a GUI config!
     if (pathEndsWith(defaultFileName, Zstr(".ffs_batch")))
         defaultFileName = beforeLast(defaultFileName, Zstr("."), IF_MISSING_RETURN_NONE) + Zstr(".ffs_real");
@@ -306,15 +306,15 @@ void MainDialog::loadConfig(const Zstring& filepath)
 void MainDialog::setLastUsedConfig(const Zstring& filepath)
 {
     //set title
-    if (filepath == lastRunConfigPath)
+    if (filepath == lastRunConfigPath_)
     {
         SetTitle(L"RealTimeSync - " + _("Automated Synchronization"));
-        currentConfigFileName.clear();
+        currentConfigFileName_.clear();
     }
     else
     {
         SetTitle(utfCvrtTo<wxString>(filepath));
-        currentConfigFileName = filepath;
+        currentConfigFileName_ = filepath;
     }
 }
 
@@ -323,7 +323,7 @@ void MainDialog::OnConfigLoad(wxCommandEvent& event)
 {
     wxFileDialog filePicker(this,
                             wxString(),
-                            utfCvrtTo<wxString>(beforeLast(currentConfigFileName, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE)), //default dir
+                            utfCvrtTo<wxString>(beforeLast(currentConfigFileName_, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE)), //default dir
                             wxString(),
                             wxString(L"RealTimeSync (*.ffs_real; *.ffs_batch)|*.ffs_real;*.ffs_batch") + L"|" +_("All files") + L" (*.*)|*",
                             wxFD_OPEN);
@@ -490,7 +490,7 @@ void MainDialog::removeAddFolder(size_t pos)
         //the deferred deletion it is expected to do (and which is implemented correctly on Windows and Linux)
         //http://bb10.com/python-wxpython-devel/2012-09/msg00004.html
         //=> since we're in a mouse button callback of a sub-component of "pairToDelete" we need to delay deletion ourselves:
-        guiQueue.processAsync([] {}, [pairToDelete] { pairToDelete->Destroy(); });
+        guiQueue_.processAsync([] {}, [pairToDelete] { pairToDelete->Destroy(); });
 
         //set size of scrolled window
         const size_t additionalRows = std::min(dirpathsExtra.size(), MAX_ADD_FOLDERS); //up to MAX_ADD_FOLDERS additional folders shall be shown
diff --git a/FreeFileSync/Source/RealTimeSync/main_dlg.h b/FreeFileSync/Source/RealTimeSync/main_dlg.h
index f540bd5d..cee7574c 100644
--- a/FreeFileSync/Source/RealTimeSync/main_dlg.h
+++ b/FreeFileSync/Source/RealTimeSync/main_dlg.h
@@ -62,10 +62,10 @@ private:
     std::vector<DirectoryPanel*> dirpathsExtra; //additional pairs to the standard pair
 
 
-    const Zstring lastRunConfigPath;
-    Zstring currentConfigFileName;
+    const Zstring lastRunConfigPath_;
+    Zstring currentConfigFileName_;
 
-    zen::AsyncGuiQueue guiQueue; //schedule and run long-running tasks asynchronously, but process results on GUI queue
+    zen::AsyncGuiQueue guiQueue_; //schedule and run long-running tasks asynchronously, but process results on GUI queue
 };
 
 #endif //MAIN_DLG_H_2384790842252445
diff --git a/FreeFileSync/Source/RealTimeSync/monitor.cpp b/FreeFileSync/Source/RealTimeSync/monitor.cpp
index c07c137c..a7902eb6 100644
--- a/FreeFileSync/Source/RealTimeSync/monitor.cpp
+++ b/FreeFileSync/Source/RealTimeSync/monitor.cpp
@@ -11,6 +11,7 @@
 #include <zen/dir_watcher.h>
 #include <zen/thread.h>
 //#include <zen/tick_count.h>
+#include <zen/basic_math.h>
 #include <wx/utils.h>
 #include "../lib/resolve_path.h"
 //#include "../library/db_file.h"     //SYNC_DB_FILE_ENDING -> complete file too much of a dependency; file ending too little to decouple into single header
@@ -22,7 +23,7 @@ using namespace zen;
 
 namespace
 {
-const int CHECK_FOLDER_INTERVAL = 1; //unit: [s]
+const int FOLDER_EXISTENCE_CHECK_INTERVAL_SEC = 1; //unit: [s]
 
 
 std::vector<Zstring> getFormattedDirs(const std::vector<Zstring>& folderPathPhrases) //throw FileError
@@ -78,7 +79,7 @@ WaitResult waitForChanges(const std::vector<Zstring>& folderPathPhrases, //throw
             //a non-existent network path may block, so check existence asynchronously!
             auto ftDirExists = runAsync([=] { return zen::dirExists(folderPathFmt); });
             //we need to check dirExists(), not somethingExists(): it's not clear if DirWatcher detects a type clash (file instead of directory!)
-            while (ftDirExists.wait_for(std::chrono::milliseconds(rts::UI_UPDATE_INTERVAL / 2)) != std::future_status::ready)
+            while (ftDirExists.wait_for(std::chrono::milliseconds(rts::UI_UPDATE_INTERVAL_MS / 2)) != std::future_status::ready)
                 onRefreshGui(false /*readyForSync*/); //may throw!
             if (!ftDirExists.get())
                 return WaitResult(folderPathFmt);
@@ -93,15 +94,16 @@ WaitResult waitForChanges(const std::vector<Zstring>& folderPathPhrases, //throw
         }
     }
 
-    auto lastCheck = std::chrono::steady_clock::now();
+    auto lastCheckTime = std::chrono::steady_clock::now();
     for (;;)
     {
         const bool checkDirExistNow = [&]() -> bool //checking once per sec should suffice
         {
             const auto now = std::chrono::steady_clock::now();
-            if (now >= lastCheck + std::chrono::seconds(CHECK_FOLDER_INTERVAL))
+
+            if (numeric::dist(now, lastCheckTime) > std::chrono::seconds(FOLDER_EXISTENCE_CHECK_INTERVAL_SEC)) //handle potential chrono wrap-around!
             {
-                lastCheck = now;
+                lastCheckTime = now;
                 return true;
             }
             return false;
@@ -145,7 +147,7 @@ WaitResult waitForChanges(const std::vector<Zstring>& folderPathPhrases, //throw
             }
         }
 
-        std::this_thread::sleep_for(std::chrono::milliseconds(rts::UI_UPDATE_INTERVAL / 2));
+        std::this_thread::sleep_for(std::chrono::milliseconds(rts::UI_UPDATE_INTERVAL_MS / 2));
         onRefreshGui(true /*readyForSync*/); //throw ?: may start sync at this presumably idle time
     }
 }
@@ -174,16 +176,16 @@ void waitForMissingDirs(const std::vector<Zstring>& folderPathPhrases, //throw F
                 //2. check dir existence
                 return zen::dirExists(folderPathFmt);
             });
-            while (ftDirExisting.wait_for(std::chrono::milliseconds(rts::UI_UPDATE_INTERVAL / 2)) != std::future_status::ready)
+            while (ftDirExisting.wait_for(std::chrono::milliseconds(rts::UI_UPDATE_INTERVAL_MS / 2)) != std::future_status::ready)
                 onRefreshGui(folderPathFmt); //may throw!
 
             if (!ftDirExisting.get())
             {
                 allExisting = false;
                 //wait some time...
-                const int refreshInterval = rts::UI_UPDATE_INTERVAL / 2;
-                static_assert(CHECK_FOLDER_INTERVAL * 1000 % refreshInterval == 0, "");
-                for (int i = 0; i < CHECK_FOLDER_INTERVAL * 1000 / refreshInterval; ++i)
+                const int refreshInterval = rts::UI_UPDATE_INTERVAL_MS / 2;
+                static_assert(FOLDER_EXISTENCE_CHECK_INTERVAL_SEC * 1000 % refreshInterval == 0, "");
+                for (int i = 0; i < FOLDER_EXISTENCE_CHECK_INTERVAL_SEC * 1000 / refreshInterval; ++i)
                 {
                     onRefreshGui(folderPathFmt); //may throw!
                     std::this_thread::sleep_for(std::chrono::milliseconds(refreshInterval));
diff --git a/FreeFileSync/Source/RealTimeSync/monitor.h b/FreeFileSync/Source/RealTimeSync/monitor.h
index 4d3538fd..8fb7ae3f 100644
--- a/FreeFileSync/Source/RealTimeSync/monitor.h
+++ b/FreeFileSync/Source/RealTimeSync/monitor.h
@@ -13,7 +13,7 @@
 
 namespace rts
 {
-const int UI_UPDATE_INTERVAL = 100; //unit: [ms]; perform ui updates not more often than necessary, 100 seems to be a good value with only a minimal performance loss
+const int UI_UPDATE_INTERVAL_MS = 100; //unit: [ms]; perform ui updates not more often than necessary, 100 seems to be a good value with only a minimal performance loss
 
 
 struct MonitorCallback
diff --git a/FreeFileSync/Source/RealTimeSync/tray_menu.cpp b/FreeFileSync/Source/RealTimeSync/tray_menu.cpp
index c421ff72..83da8f86 100644
--- a/FreeFileSync/Source/RealTimeSync/tray_menu.cpp
+++ b/FreeFileSync/Source/RealTimeSync/tray_menu.cpp
@@ -5,8 +5,8 @@
 // *****************************************************************************
 
 #include "tray_menu.h"
+#include <chrono>
 #include <zen/thread.h>
-#include <zen/tick_count.h>
 #include <wx/taskbar.h>
 #include <wx/icon.h> //Linux needs this
 #include <wx/app.h>
@@ -25,15 +25,16 @@ using namespace zen;
 
 namespace
 {
-const int RETRY_AFTER_ERROR_INTERVAL = 15; //unit: [s]
+const int RETRY_AFTER_ERROR_INTERVAL_SEC = 15; //unit: [s]
+
+std::chrono::steady_clock::time_point lastExec;
 
-const std::int64_t TICKS_UPDATE_INTERVAL = rts::UI_UPDATE_INTERVAL* ticksPerSec() / 1000;
-TickVal lastExec = getTicks();
 
 bool updateUiIsAllowed()
 {
-    const TickVal now = getTicks(); //0 on error
-    if (dist(lastExec, now) >= TICKS_UPDATE_INTERVAL)  //perform ui updates not more often than necessary
+    const auto now = std::chrono::steady_clock::now();
+
+    if (numeric::dist(now, lastExec) > std::chrono::milliseconds(rts::UI_UPDATE_INTERVAL_MS)) //handle potential chrono wrap-around!
     {
         lastExec = now;
         return true;
@@ -307,8 +308,8 @@ rts::AbortReason rts::startDirectoryMonitor(const xmlAccess::XmlRealConfig& conf
             trayIcon.clearShowErrorRequested();
 
             //wait for some time, then return to retry
-            static_assert(RETRY_AFTER_ERROR_INTERVAL * 1000 % UI_UPDATE_INTERVAL == 0, "");
-            for (int i = 0; i < RETRY_AFTER_ERROR_INTERVAL * 1000 / UI_UPDATE_INTERVAL; ++i)
+            static_assert(RETRY_AFTER_ERROR_INTERVAL_SEC * 1000 % UI_UPDATE_INTERVAL_MS == 0, "");
+            for (int i = 0; i < RETRY_AFTER_ERROR_INTERVAL_SEC * 1000 / UI_UPDATE_INTERVAL_MS; ++i)
             {
                 trayIcon.doUiRefreshNow(); //throw AbortMonitoring
 
@@ -321,7 +322,7 @@ rts::AbortReason rts::startDirectoryMonitor(const xmlAccess::XmlRealConfig& conf
                         case ConfirmationButton::CANCEL:
                             throw AbortMonitoring(SHOW_GUI);
                     }
-                std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL));
+                std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS));
             }
         }
 
diff --git a/FreeFileSync/Source/algorithm.cpp b/FreeFileSync/Source/algorithm.cpp
index 5dba0989..1def34af 100644
--- a/FreeFileSync/Source/algorithm.cpp
+++ b/FreeFileSync/Source/algorithm.cpp
@@ -329,14 +329,14 @@ public:
 
 private:
     DetectMovedFiles(BaseFolderPair& baseFolder, const InSyncFolder& dbFolder) :
-        cmpVar           (baseFolder.getCompVariant()),
-        fileTimeTolerance(baseFolder.getFileTimeTolerance()),
-        ignoreTimeShiftMinutes(baseFolder.getIgnoredTimeShift())
+        cmpVar_           (baseFolder.getCompVariant()),
+        fileTimeTolerance_(baseFolder.getFileTimeTolerance()),
+        ignoreTimeShiftMinutes_(baseFolder.getIgnoredTimeShift())
     {
         recurse(baseFolder, &dbFolder);
 
-        if ((!exLeftOnlyById .empty() || !exLeftOnlyByPath .empty()) &&
-            (!exRightOnlyById.empty() || !exRightOnlyByPath.empty()))
+        if ((!exLeftOnlyById_ .empty() || !exLeftOnlyByPath_ .empty()) &&
+            (!exRightOnlyById_.empty() || !exRightOnlyByPath_.empty()))
             detectMovePairs(dbFolder);
     }
 
@@ -360,10 +360,10 @@ private:
             if (cat == FILE_LEFT_SIDE_ONLY)
             {
                 if (const InSyncFile* dbFile = getDbFileEntry())
-                    exLeftOnlyByPath.emplace(dbFile, &file);
+                    exLeftOnlyByPath_.emplace(dbFile, &file);
                 else if (!file.getFileId<LEFT_SIDE>().empty())
                 {
-                    auto rv = exLeftOnlyById.emplace(file.getFileId<LEFT_SIDE>(), &file);
+                    auto rv = exLeftOnlyById_.emplace(file.getFileId<LEFT_SIDE>(), &file);
                     if (!rv.second) //duplicate file ID! NTFS hard link/symlink?
                         rv.first->second = nullptr;
                 }
@@ -371,10 +371,10 @@ private:
             else if (cat == FILE_RIGHT_SIDE_ONLY)
             {
                 if (const InSyncFile* dbFile = getDbFileEntry())
-                    exRightOnlyByPath.emplace(dbFile, &file);
+                    exRightOnlyByPath_.emplace(dbFile, &file);
                 else if (!file.getFileId<RIGHT_SIDE>().empty())
                 {
-                    auto rv = exRightOnlyById.emplace(file.getFileId<RIGHT_SIDE>(), &file);
+                    auto rv = exRightOnlyById_.emplace(file.getFileId<RIGHT_SIDE>(), &file);
                     if (!rv.second) //duplicate file ID! NTFS hard link/symlink?
                         rv.first->second = nullptr;
                 }
@@ -443,10 +443,10 @@ private:
 
     void findAndSetMovePair(const InSyncFile& dbFile) const
     {
-        if (stillInSync(dbFile, cmpVar, fileTimeTolerance, ignoreTimeShiftMinutes))
-            if (FilePair* fileLeftOnly = getAssocFilePair<LEFT_SIDE>(dbFile, exLeftOnlyById, exLeftOnlyByPath))
+        if (stillInSync(dbFile, cmpVar_, fileTimeTolerance_, ignoreTimeShiftMinutes_))
+            if (FilePair* fileLeftOnly = getAssocFilePair<LEFT_SIDE>(dbFile, exLeftOnlyById_, exLeftOnlyByPath_))
                 if (sameSizeAndDate<LEFT_SIDE>(*fileLeftOnly, dbFile))
-                    if (FilePair* fileRightOnly = getAssocFilePair<RIGHT_SIDE>(dbFile, exRightOnlyById, exRightOnlyByPath))
+                    if (FilePair* fileRightOnly = getAssocFilePair<RIGHT_SIDE>(dbFile, exRightOnlyById_, exRightOnlyByPath_))
                         if (sameSizeAndDate<RIGHT_SIDE>(*fileRightOnly, dbFile))
                             if (fileLeftOnly ->getMoveRef() == nullptr && //don't let a row participate in two move pairs!
                                 fileRightOnly->getMoveRef() == nullptr)   //
@@ -456,16 +456,16 @@ private:
                             }
     }
 
-    const CompareVariant cmpVar;
-    const int fileTimeTolerance;
-    const std::vector<unsigned int> ignoreTimeShiftMinutes;
+    const CompareVariant cmpVar_;
+    const int fileTimeTolerance_;
+    const std::vector<unsigned int> ignoreTimeShiftMinutes_;
 
-    std::unordered_map<AFS::FileId, FilePair*, StringHash> exLeftOnlyById;  //FilePair* == nullptr for duplicate ids! => consider aliasing through symlinks!
-    std::unordered_map<AFS::FileId, FilePair*, StringHash> exRightOnlyById; //=> avoid ambiguity for mixtures of files/symlinks on one side and allow 1-1 mapping only!
+    std::unordered_map<AFS::FileId, FilePair*, StringHash> exLeftOnlyById_;  //FilePair* == nullptr for duplicate ids! => consider aliasing through symlinks!
+    std::unordered_map<AFS::FileId, FilePair*, StringHash> exRightOnlyById_; //=> avoid ambiguity for mixtures of files/symlinks on one side and allow 1-1 mapping only!
     //MSVC: std::unordered_map: about twice as fast as std::map for 1 million items!
 
-    std::unordered_map<const InSyncFile*, FilePair*> exLeftOnlyByPath; //MSVC: only 4% faster than std::map for 1 million items!
-    std::unordered_map<const InSyncFile*, FilePair*> exRightOnlyByPath;
+    std::unordered_map<const InSyncFile*, FilePair*> exLeftOnlyByPath_; //MSVC: only 4% faster than std::map for 1 million items!
+    std::unordered_map<const InSyncFile*, FilePair*> exRightOnlyByPath_;
     /*
     detect renamed files:
 
@@ -502,12 +502,9 @@ public:
 
 private:
     RedetermineTwoWay(BaseFolderPair& baseFolder, const InSyncFolder& dbFolder) :
-        txtBothSidesChanged(_("Both sides have changed since last synchronization.")),
-        txtNoSideChanged(_("Cannot determine sync-direction:") + L" \n" + _("No change since last synchronization.")),
-        txtDbNotInSync(_("Cannot determine sync-direction:") + L" \n" + _("The database entry is not in sync considering current settings.")),
-        cmpVar                (baseFolder.getCompVariant()),
-        fileTimeTolerance     (baseFolder.getFileTimeTolerance()),
-        ignoreTimeShiftMinutes(baseFolder.getIgnoredTimeShift())
+        cmpVar_                (baseFolder.getCompVariant()),
+        fileTimeTolerance_     (baseFolder.getFileTimeTolerance()),
+        ignoreTimeShiftMinutes_(baseFolder.getIgnoredTimeShift())
     {
         //-> considering filter not relevant:
         //if narrowing filter: all ok; if widening filter (if file ex on both sides -> conflict, fine; if file ex. on one side: copy to other side: fine)
@@ -548,13 +545,13 @@ private:
         }
 
         //evaluation
-        const bool changeOnLeft  = !matchesDbEntry< LEFT_SIDE>(file, dbEntry, ignoreTimeShiftMinutes);
-        const bool changeOnRight = !matchesDbEntry<RIGHT_SIDE>(file, dbEntry, ignoreTimeShiftMinutes);
+        const bool changeOnLeft  = !matchesDbEntry< LEFT_SIDE>(file, dbEntry, ignoreTimeShiftMinutes_);
+        const bool changeOnRight = !matchesDbEntry<RIGHT_SIDE>(file, dbEntry, ignoreTimeShiftMinutes_);
 
         if (changeOnLeft != changeOnRight)
         {
             //if database entry not in sync according to current settings! -> set direction based on sync status only!
-            if (dbEntry && !stillInSync(dbEntry->second, cmpVar, fileTimeTolerance, ignoreTimeShiftMinutes))
+            if (dbEntry && !stillInSync(dbEntry->second, cmpVar_, fileTimeTolerance_, ignoreTimeShiftMinutes_))
                 file.setSyncDirConflict(txtDbNotInSync);
             else
                 file.setSyncDir(changeOnLeft ? SyncDirection::RIGHT : SyncDirection::LEFT);
@@ -584,13 +581,13 @@ private:
         }
 
         //evaluation
-        const bool changeOnLeft  = !matchesDbEntry< LEFT_SIDE>(symlink, dbEntry, ignoreTimeShiftMinutes);
-        const bool changeOnRight = !matchesDbEntry<RIGHT_SIDE>(symlink, dbEntry, ignoreTimeShiftMinutes);
+        const bool changeOnLeft  = !matchesDbEntry< LEFT_SIDE>(symlink, dbEntry, ignoreTimeShiftMinutes_);
+        const bool changeOnRight = !matchesDbEntry<RIGHT_SIDE>(symlink, dbEntry, ignoreTimeShiftMinutes_);
 
         if (changeOnLeft != changeOnRight)
         {
             //if database entry not in sync according to current settings! -> set direction based on sync status only!
-            if (dbEntry && !stillInSync(dbEntry->second, cmpVar, fileTimeTolerance, ignoreTimeShiftMinutes))
+            if (dbEntry && !stillInSync(dbEntry->second, cmpVar_, fileTimeTolerance_, ignoreTimeShiftMinutes_))
                 symlink.setSyncDirConflict(txtDbNotInSync);
             else
                 symlink.setSyncDir(changeOnLeft ? SyncDirection::RIGHT : SyncDirection::LEFT);
@@ -650,13 +647,13 @@ private:
         recurse(folder, dbEntry ? &dbEntry->second : nullptr);
     }
 
-    const std::wstring txtBothSidesChanged;
-    const std::wstring txtNoSideChanged;
-    const std::wstring txtDbNotInSync;
+    const std::wstring txtBothSidesChanged = _("Both sides have changed since last synchronization.");
+    const std::wstring txtNoSideChanged    = _("Cannot determine sync-direction:") + L" \n" + _("No change since last synchronization.");
+    const std::wstring txtDbNotInSync      = _("Cannot determine sync-direction:") + L" \n" + _("The database entry is not in sync considering current settings.");
 
-    const CompareVariant cmpVar;
-    const int fileTimeTolerance;
-    const std::vector<unsigned int> ignoreTimeShiftMinutes;
+    const CompareVariant cmpVar_;
+    const int fileTimeTolerance_;
+    const std::vector<unsigned int> ignoreTimeShiftMinutes_;
 };
 }
 
@@ -1572,7 +1569,7 @@ void TempFileBuffer::createTempFiles(const std::set<FileDetails>& workLoad, Proc
             tempPathTmp += Zstr("FFS-");
 
             const std::string guid = generateGUID(); //no need for full-blown (pseudo-)random numbers for this one-time invocation
-            const uint32_t crc32 = getCrc32(guid.begin(), guid.end());
+            const uint32_t crc32 = getCrc32(guid);
             tempPathTmp += printNumber<Zstring>(Zstr("%08x"), static_cast<unsigned int>(crc32));
 
             makeDirectoryRecursively(tempPathTmp); //throw FileError
@@ -1593,7 +1590,7 @@ void TempFileBuffer::createTempFiles(const std::set<FileDetails>& workLoad, Proc
         writeNumber   (cookie, details.descr.isFollowedSymlink);
         writeContainer(cookie, AFS::getInitPathPhrase(details.path));
 
-        const uint16_t crc16 = getCrc16(cookie.ref().begin(), cookie.ref().end());
+        const uint16_t crc16 = getCrc16(cookie.ref());
         const Zstring detailsHash = printNumber<Zstring>(Zstr("%04x"), static_cast<unsigned int>(crc16));
 
         const Zstring fileName = AFS::getFileShortName(details.path);
diff --git a/FreeFileSync/Source/application.cpp b/FreeFileSync/Source/application.cpp
index 1a86d915..15aa04a0 100644
--- a/FreeFileSync/Source/application.cpp
+++ b/FreeFileSync/Source/application.cpp
@@ -18,17 +18,15 @@
 #include "synchronization.h"
 #include "ui/batch_status_handler.h"
 #include "ui/main_dlg.h"
-#include "ui/switch_to_gui.h"
 #include "lib/help_provider.h"
 #include "lib/process_xml.h"
 #include "lib/error_log.h"
 #include "lib/resolve_path.h"
 
 #ifdef ZEN_WIN
-    #include <zen/win_ver.h>
-    //#include <zen/dll.h>
-    #include "lib/app_user_mode_id.h"
     #include <zen/service_notification.h>
+    #include "lib/app_user_mode_id.h"
+    #include "ui/version_check.h"
 
 #elif defined ZEN_LINUX
     #include <gtk/gtk.h>
@@ -67,21 +65,21 @@ std::vector<Zstring> getCommandlineArgs(const wxApp& app)
     while (endsWith(cmdLine, L' ')) //may end with space
         cmdLine.pop_back();
 
-    auto iterStart = cmdLine.end(); //end() means: no token
+    auto itStart = cmdLine.end(); //end() means: no token
     for (auto it = cmdLine.begin(); it != cmdLine.end(); ++it)
         if (*it == L' ') //space commits token
         {
-            if (iterStart != cmdLine.end())
+            if (itStart != cmdLine.end())
             {
-                args.emplace_back(iterStart, it);
-                iterStart = cmdLine.end(); //expect consecutive blanks!
+                args.emplace_back(itStart, it);
+                itStart = cmdLine.end(); //expect consecutive blanks!
             }
         }
         else
         {
             //start new token
-            if (iterStart == cmdLine.end())
-                iterStart = it;
+            if (itStart == cmdLine.end())
+                itStart = it;
 
             if (*it == L'\"')
             {
@@ -90,8 +88,8 @@ std::vector<Zstring> getCommandlineArgs(const wxApp& app)
                     break;
             }
         }
-    if (iterStart != cmdLine.end())
-        args.emplace_back(iterStart, cmdLine.end());
+    if (itStart != cmdLine.end())
+        args.emplace_back(itStart, cmdLine.end());
 
     if (!args.empty())
         args.erase(args.begin()); //remove first argument which is exe path by convention: https://blogs.msdn.microsoft.com/oldnewthing/20060515-07/?p=31203
@@ -131,7 +129,7 @@ bool Application::OnInit()
 
 #elif defined ZEN_LINUX
     ::gtk_init(nullptr, nullptr);
-    //::gtk_rc_parse((getResourceDir() + "styles.gtk_rc").c_str()); //remove inner border from bitmap buttons
+    //::gtk_rc_parse((getResourceDirPf() + "styles.gtk_rc").c_str()); //remove inner border from bitmap buttons
 #endif
 
     //Windows User Experience Interaction Guidelines: tool tips should have 5s timeout, info tips no timeout => compromise:
@@ -140,17 +138,27 @@ bool Application::OnInit()
 
     SetAppName(L"FreeFileSync"); //if not set, the default is the executable's name!
 
-    initResourceImages(getResourceDir() + Zstr("Resources.zip"));
+    initResourceImages(getResourceDirPf() + Zstr("Resources.zip"));
+
+    try
+    {
+        //tentatively set program language to OS default until GlobalSettings.xml is read later
+        setLanguage(xmlAccess::XmlGlobalSettings().programLanguage); //throw FileError
+    }
+    catch (const FileError&) { assert(false); }
 
     Connect(wxEVT_QUERY_END_SESSION, wxEventHandler(Application::onQueryEndSession), nullptr, this);
     Connect(wxEVT_END_SESSION,       wxEventHandler(Application::onQueryEndSession), nullptr, this);
 
+#ifdef ZEN_WIN
+    runSanityChecks();
+#endif
+
     //do not call wxApp::OnInit() to avoid using wxWidgets command line parser
 
     //Note: app start is deferred: batch mode requires the wxApp eventhandler to be established for UI update events. This is not the case at the time of OnInit()!
     Connect(EVENT_ENTER_EVENT_LOOP, wxEventHandler(Application::onEnterEventLoop), nullptr, this);
     AddPendingEvent(wxCommandEvent(EVENT_ENTER_EVENT_LOOP));
-
     return true; //true: continue processing; false: exit immediately.
 }
 
@@ -251,13 +259,6 @@ void Application::launch(const std::vector<Zstring>& commandArgs)
     wxTheApp->SetExitOnFrameDelete(false); //prevent popup-windows from becoming temporary top windows leading to program exit after closure
     ZEN_ON_SCOPE_EXIT(if (!mainWindowWasSet()) wxTheApp->ExitMainLoop();); //quit application, if no main window was set (batch silent mode)
 
-    try
-    {
-        //tentatively set program language to OS default until GlobalSettings.xml is read later
-        setLanguage(xmlAccess::XmlGlobalSettings().programLanguage); //throw FileError
-    }
-    catch (const FileError&) { assert(false); }
-
     auto notifyFatalError = [&](const std::wstring& msg, const std::wstring& title)
     {
         auto titleTmp = copyStringTo<std::wstring>(wxTheApp->GetAppDisplayName()) + L" - " + title;
@@ -595,10 +596,8 @@ void runBatchMode(const Zstring& globalConfigFile, const XmlBatchConfig& batchCf
     {
         const TimeComp timeStamp = localTime();
 
-        const SwitchToGui switchBatchToGui(globalConfigFile, globalCfg, referenceFile, batchCfg); //prepare potential operational switch
-
         //class handling status updates and error messages
-        BatchStatusHandler statusHandler(!batchCfg.runMinimized, //throw BatchAbortProcess
+        BatchStatusHandler statusHandler(!batchCfg.runMinimized, //throw BatchAbortProcess, BatchRequestSwitchToMainDialog
                                          extractJobName(referenceFile),
                                          globalCfg.soundFileSyncFinished,
                                          timeStamp,
@@ -608,7 +607,6 @@ void runBatchMode(const Zstring& globalConfigFile, const XmlBatchConfig& batchCf
                                          batchCfg.handleError,
                                          globalCfg.automaticRetryCount,
                                          globalCfg.automaticRetryDelay,
-                                         switchBatchToGui,
                                          returnCode,
                                          batchCfg.mainCfg.onCompletion,
                                          globalCfg.gui.onCompletionHistory);
@@ -640,7 +638,7 @@ void runBatchMode(const Zstring& globalConfigFile, const XmlBatchConfig& batchCf
                                              globalCfg.createLockFile,
                                              dirLocks,
                                              cmpConfig,
-                                             statusHandler);
+                                             statusHandler); //throw ?
 
         //START SYNCHRONIZATION
         const std::vector<FolderPairSyncCfg> syncProcessCfg = extractSyncCfg(batchCfg.mainCfg);
@@ -657,9 +655,14 @@ void runBatchMode(const Zstring& globalConfigFile, const XmlBatchConfig& batchCf
                     globalCfg.folderAccessTimeout,
                     syncProcessCfg,
                     cmpResult,
-                    statusHandler);
+                    statusHandler); //throw ?
     }
     catch (BatchAbortProcess&) {} //exit used by statusHandler
+    catch (BatchRequestSwitchToMainDialog&)
+    {
+        //open new toplevel window *after* progress dialog is gone => run on main event loop
+        return MainDialog::create(globalConfigFile, &globalCfg, xmlAccess::convertBatchToGui(batchCfg), { referenceFile }, true /*startComparison*/);
+    }
 
     try //save global settings to XML: e.g. ignored warnings
     {
diff --git a/FreeFileSync/Source/comparison.cpp b/FreeFileSync/Source/comparison.cpp
index 4b251e8b..36318542 100644
--- a/FreeFileSync/Source/comparison.cpp
+++ b/FreeFileSync/Source/comparison.cpp
@@ -45,11 +45,6 @@ namespace
 {
 struct ResolvedFolderPair
 {
-    ResolvedFolderPair(const AbstractPath& left,
-                       const AbstractPath& right) :
-        folderPathLeft (left),
-        folderPathRight(right) {}
-
     AbstractPath folderPathLeft;
     AbstractPath folderPathRight;
 };
@@ -83,7 +78,7 @@ ResolvedBaseFolders initializeBaseFolders(const std::vector<FolderPairCfg>& cfgL
             uniqueBaseFolders.insert(folderPathLeft);
             uniqueBaseFolders.insert(folderPathRight);
 
-            output.resolvedPairs.emplace_back(folderPathLeft, folderPathRight);
+            output.resolvedPairs.push_back({ folderPathLeft, folderPathRight });
         }
 
         const FolderStatus status = getFolderStatusNonBlocking(uniqueBaseFolders, folderAccessTimeout, allowUserInteraction, callback); //re-check *all* directories on each try!
@@ -128,7 +123,7 @@ void checkForIncompleteInput(const std::vector<ResolvedFolderPair>& folderPairs,
         else if (!AFS::isNullPath(fp.folderPathLeft))
             haveFullPair = true;
 
-    if (havePartialPair == haveFullPair) //error if: all empty or exist both full and partial pairs -> support single-dir scenario
+    if (havePartialPair == haveFullPair) //error if: all empty or exist both full and partial pairs -> support single-folder comparison scenario
         callback.reportWarning(_("A folder input field is empty.") + L" \n\n" +
                                _("The corresponding folder will be considered as empty."), warningInputFieldEmpty);
 }
@@ -179,7 +174,7 @@ private:
                                                       std::vector<FilePair*>& undefinedFiles,
                                                       std::vector<SymlinkPair*>& undefinedSymlinks) const;
 
-    std::map<DirectoryKey, DirectoryValue> directoryBuffer; //contains only *existing* directories
+    std::map<DirectoryKey, DirectoryValue> directoryBuffer_; //contains only *existing* directories
     const int fileTimeTolerance_;
     ProcessCallback& callback_;
 };
@@ -195,8 +190,8 @@ ComparisonBuffer::ComparisonBuffer(const std::set<DirectoryKey>& keysToRead, int
 
         void reportStatus(const std::wstring& statusMsg, int itemsTotal) override
         {
-            callback_.updateProcessedData(itemsTotal - itemsReported, 0); //processed bytes are reported in subfunctions!
-            itemsReported = itemsTotal;
+            callback_.updateProcessedData(itemsTotal - itemsReported_, 0); //processed bytes are reported in subfunctions!
+            itemsReported_ = itemsTotal;
 
             callback_.reportStatus(statusMsg); //may throw
             //callback_.requestUiRefresh(); //already called by reportStatus()
@@ -219,13 +214,13 @@ ComparisonBuffer::ComparisonBuffer(const std::set<DirectoryKey>& keysToRead, int
 
     private:
         ProcessCallback& callback_;
-        int itemsReported = 0;
+        int itemsReported_ = 0;
     } cb(callback);
 
     fillBuffer(keysToRead, //in
-               directoryBuffer, //out
+               directoryBuffer_, //out
                cb,
-               UI_UPDATE_INTERVAL / 2); //every ~50 ms
+               UI_UPDATE_INTERVAL_MS / 2); //every ~50 ms
 }
 
 
@@ -233,38 +228,39 @@ ComparisonBuffer::ComparisonBuffer(const std::set<DirectoryKey>& keysToRead, int
 
 //const wchar_t arrowLeft [] = L"\u2190";
 //const wchar_t arrowRight[] = L"\u2192"; unicode arrows -> too small
-const wchar_t arrowLeft [] = L"<--";
-const wchar_t arrowRight[] = L"-->";
+const wchar_t arrowLeft [] = L"<-";
+const wchar_t arrowRight[] = L"->";
 
+//NOTE: conflict texts are NOT expected to contain additional path info (already implicit through associated item!)
+//      => only add path info if information is relevant, e.g. conflict is specific to left/right side only
 
-//check for very old dates or dates in the future
-std::wstring getConflictInvalidDate(const std::wstring& displayPath, std::int64_t utcTime)
+template <SelectedSide side, class FileOrLinkPair> inline
+std::wstring getConflictInvalidDate(const FileOrLinkPair& file)
 {
-    return replaceCpy(_("File %x has an invalid date."), L"%x", fmtPath(displayPath)) + L"\n" +
-           _("Date:") + L" " + utcToLocalTimeString(utcTime);
+    return replaceCpy(_("File %x has an invalid date."), L"%x", fmtPath(AFS::getDisplayPath(file.template getAbstractPath<side>()))) + L"\n" +
+           _("Date:") + L" " + utcToLocalTimeString(file.template getLastWriteTime<side>());
 }
 
 
-//check for changed files with same modification date
 std::wstring getConflictSameDateDiffSize(const FilePair& file)
 {
-    return replaceCpy(_("Files %x have the same date but a different size."), L"%x", fmtPath(file.getPairRelativePath())) + L"\n" +
-           L"    " + arrowLeft  + L" " + _("Date:") + L" " + utcToLocalTimeString(file.getLastWriteTime< LEFT_SIDE>()) + L"    " + _("Size:") + L" " + toGuiString(file.getFileSize<LEFT_SIDE>()) + L"\n" +
-           L"    " + arrowRight + L" " + _("Date:") + L" " + utcToLocalTimeString(file.getLastWriteTime<RIGHT_SIDE>()) + L"    " + _("Size:") + L" " + toGuiString(file.getFileSize<RIGHT_SIDE>());
+    return _("Files have the same date but a different size.") + L"\n" +
+           arrowLeft  + L" " + _("Date:") + L" " + utcToLocalTimeString(file.getLastWriteTime< LEFT_SIDE>()) + L"    " + _("Size:") + L" " + toGuiString(file.getFileSize<LEFT_SIDE>()) + L"\n" +
+           arrowRight + L" " + _("Date:") + L" " + utcToLocalTimeString(file.getLastWriteTime<RIGHT_SIDE>()) + L"    " + _("Size:") + L" " + toGuiString(file.getFileSize<RIGHT_SIDE>());
 }
 
 
 std::wstring getConflictSkippedBinaryComparison(const FilePair& file)
 {
-    return replaceCpy(_("Content comparison was skipped for excluded files %x."), L"%x", fmtPath(file.getPairRelativePath()));
+    return _("Content comparison was skipped for excluded files.");
 }
 
 
 std::wstring getDescrDiffMetaShortnameCase(const FileSystemObject& fsObj)
 {
     return _("Items differ in attributes only") + L"\n" +
-           L"    " + arrowLeft  + L" " + fmtPath(fsObj.getItemName< LEFT_SIDE>()) + L"\n" +
-           L"    " + arrowRight + L" " + fmtPath(fsObj.getItemName<RIGHT_SIDE>());
+           arrowLeft  + L" " + fmtPath(fsObj.getItemName< LEFT_SIDE>()) + L"\n" +
+           arrowRight + L" " + fmtPath(fsObj.getItemName<RIGHT_SIDE>());
 }
 
 
@@ -272,8 +268,8 @@ template <class FileOrLinkPair>
 std::wstring getDescrDiffMetaDate(const FileOrLinkPair& file)
 {
     return _("Items differ in attributes only") + L"\n" +
-           L"    " + arrowLeft  + L" " + _("Date:") + L" " + utcToLocalTimeString(file.template getLastWriteTime< LEFT_SIDE>()) + L"\n" +
-           L"    " + arrowRight + L" " + _("Date:") + L" " + utcToLocalTimeString(file.template getLastWriteTime<RIGHT_SIDE>());
+           arrowLeft  + L" " + _("Date:") + L" " + utcToLocalTimeString(file.template getLastWriteTime< LEFT_SIDE>()) + L"\n" +
+           arrowRight + L" " + _("Date:") + L" " + utcToLocalTimeString(file.template getLastWriteTime<RIGHT_SIDE>());
 }
 
 //-----------------------------------------------------------------------------
@@ -304,11 +300,11 @@ void categorizeSymlinkByTime(SymlinkPair& symlink)
             break;
 
         case TimeResult::LEFT_INVALID:
-            symlink.setCategoryConflict(getConflictInvalidDate(AFS::getDisplayPath(symlink.getAbstractPath<LEFT_SIDE>()), symlink.getLastWriteTime<LEFT_SIDE>()));
+            symlink.setCategoryConflict(getConflictInvalidDate<LEFT_SIDE>(symlink));
             break;
 
         case TimeResult::RIGHT_INVALID:
-            symlink.setCategoryConflict(getConflictInvalidDate(AFS::getDisplayPath(symlink.getAbstractPath<RIGHT_SIDE>()), symlink.getLastWriteTime<RIGHT_SIDE>()));
+            symlink.setCategoryConflict(getConflictInvalidDate<RIGHT_SIDE>(symlink));
             break;
     }
 }
@@ -356,11 +352,11 @@ std::shared_ptr<BaseFolderPair> ComparisonBuffer::compareByTimeSize(const Resolv
                 break;
 
             case TimeResult::LEFT_INVALID:
-                file->setCategoryConflict(getConflictInvalidDate(AFS::getDisplayPath(file->getAbstractPath<LEFT_SIDE>()), file->getLastWriteTime<LEFT_SIDE>()));
+                file->setCategoryConflict(getConflictInvalidDate<LEFT_SIDE>(*file));
                 break;
 
             case TimeResult::RIGHT_INVALID:
-                file->setCategoryConflict(getConflictInvalidDate(AFS::getDisplayPath(file->getAbstractPath<RIGHT_SIDE>()), file->getLastWriteTime<RIGHT_SIDE>()));
+                file->setCategoryConflict(getConflictInvalidDate<RIGHT_SIDE>(*file));
                 break;
         }
     }
@@ -734,7 +730,7 @@ void MergeSides::mergeTwoSides(const FolderContainer& lhs, const FolderContainer
 
 //-----------------------------------------------------------------------------------------------
 
-//mark excluded directories (see fillBuffer()) + remove superfluous excluded subdirectories
+//uncheck excluded directories (see fillBuffer()) + remove superfluous excluded subdirectories
 void stripExcludedDirectories(HierarchyObject& hierObj, const HardFilter& filterProc)
 {
     for (FolderPair& folder : hierObj.refSubFolders())
@@ -771,8 +767,8 @@ std::shared_ptr<BaseFolderPair> ComparisonBuffer::performComparison(const Resolv
 
     auto getDirValue = [&](const AbstractPath& folderPath) -> const DirectoryValue*
     {
-        auto it = directoryBuffer.find(DirectoryKey(folderPath, fpCfg.filter.nameFilter, fpCfg.handleSymlinks));
-        return it != directoryBuffer.end() ? &it->second : nullptr;
+        auto it = directoryBuffer_.find(DirectoryKey(folderPath, fpCfg.filter.nameFilter, fpCfg.handleSymlinks));
+        return it != directoryBuffer_.end() ? &it->second : nullptr;
     };
 
     const DirectoryValue* bufValueLeft  = getDirValue(fp.folderPathLeft);
@@ -904,26 +900,23 @@ FolderComparison zen::compare(xmlAccess::OptionalDialogs& warnings,
         callback.reportInfo(e.toString()); //may throw!
     }
 
-    //-------------------some basic checks:------------------------------------------
-
     const ResolvedBaseFolders& resInfo = initializeBaseFolders(cfgList, folderAccessTimeout, allowUserInteraction, callback);
-
     //directory existence only checked *once* to avoid race conditions!
     if (resInfo.resolvedPairs.size() != cfgList.size())
         throw std::logic_error("Contract violation! " + std::string(__FILE__) + ":" + numberTo<std::string>(__LINE__));
 
+    auto basefolderExisting = [&](const AbstractPath& folderPath) { return resInfo.existingBaseFolders.find(folderPath) != resInfo.existingBaseFolders.end(); };
+
+    //-----------execute basic checks all at once before starting comparison----------
+
     checkForIncompleteInput(resInfo.resolvedPairs, warnings.warningInputFieldEmpty,  callback);
     checkFolderDependency  (resInfo.resolvedPairs, warnings.warningDependentFolders, callback);
 
-    //list of directories that are *expected* to be existent (and need to be scanned)!
-
     //-------------------end of basic checks------------------------------------------
 
-    auto basefolderExisting = [&](const AbstractPath& folderPath) { return resInfo.existingBaseFolders.find(folderPath) != resInfo.existingBaseFolders.end(); };
-
-    std::vector<std::pair<ResolvedFolderPair, FolderPairCfg>> totalWorkLoad;
+    std::vector<std::pair<ResolvedFolderPair, FolderPairCfg>> workLoad;
     for (size_t i = 0; i < cfgList.size(); ++i)
-        totalWorkLoad.emplace_back(resInfo.resolvedPairs[i], cfgList[i]);
+        workLoad.emplace_back(resInfo.resolvedPairs[i], cfgList[i]);
 
     //lock (existing) directories before comparison
     if (createDirLocks)
@@ -941,9 +934,9 @@ FolderComparison zen::compare(xmlAccess::OptionalDialogs& warnings,
         //------------------- fill directory buffer ---------------------------------------------------
         std::set<DirectoryKey> dirsToRead;
 
-        for (const auto& w : totalWorkLoad)
+        for (const auto& w : workLoad)
         {
-            if (basefolderExisting(w.first.folderPathLeft)) //only traverse *currently existing* directories: at this point user is aware that non-ex + empty string are seen as empty folder!
+            if (basefolderExisting(w.first.folderPathLeft)) //only traverse *currently existing* folders: at this point user is aware that non-ex + empty string are seen as empty folder!
                 dirsToRead.emplace(w.first.folderPathLeft,  w.second.filter.nameFilter, w.second.handleSymlinks);
             if (basefolderExisting(w.first.folderPathRight))
                 dirsToRead.emplace(w.first.folderPathRight, w.second.filter.nameFilter, w.second.handleSymlinks);
@@ -960,7 +953,7 @@ FolderComparison zen::compare(xmlAccess::OptionalDialogs& warnings,
 
             //process binary comparison as one junk
             std::vector<std::pair<ResolvedFolderPair, FolderPairCfg>> workLoadByContent;
-            for (const auto& w : totalWorkLoad)
+            for (const auto& w : workLoad)
                 switch (w.second.compareVar)
                 {
                     case CompareVariant::TIME_SIZE:
@@ -973,7 +966,7 @@ FolderComparison zen::compare(xmlAccess::OptionalDialogs& warnings,
             std::list<std::shared_ptr<BaseFolderPair>> outputByContent = cmpBuff.compareByContent(workLoadByContent);
 
             //write output in expected order
-            for (const auto& w : totalWorkLoad)
+            for (const auto& w : workLoad)
                 switch (w.second.compareVar)
                 {
                     case CompareVariant::TIME_SIZE:
@@ -996,14 +989,14 @@ FolderComparison zen::compare(xmlAccess::OptionalDialogs& warnings,
 
         //--------- set initial sync-direction --------------------------------------------------
 
-        for (auto j = begin(output); j != end(output); ++j)
+        for (auto it = begin(output); it != end(output); ++it)
         {
-            const FolderPairCfg& fpCfg = cfgList[j - output.begin()];
+            const FolderPairCfg& fpCfg = cfgList[it - output.begin()];
 
             callback.reportStatus(_("Calculating sync directions..."));
             callback.forceUiRefresh();
 
-            zen::redetermineSyncDirection(fpCfg.directionCfg, *j,
+            zen::redetermineSyncDirection(fpCfg.directionCfg, *it,
             [&](const std::wstring& warning) { callback.reportWarning(warning, warnings.warningDatabaseError); },
             [&](std::int64_t bytesDelta) { callback.requestUiRefresh(); });//throw X
         }
diff --git a/FreeFileSync/Source/file_hierarchy.cpp b/FreeFileSync/Source/file_hierarchy.cpp
index 98b72662..0d517525 100644
--- a/FreeFileSync/Source/file_hierarchy.cpp
+++ b/FreeFileSync/Source/file_hierarchy.cpp
@@ -144,6 +144,9 @@ bool hasDirectChild(const HierarchyObject& hierObj, Predicate p)
            std::any_of(hierObj.refSubLinks  ().begin(), hierObj.refSubLinks  ().end(), p) ||
            std::any_of(hierObj.refSubFolders().begin(), hierObj.refSubFolders().end(), p);
 }
+
+const wchar_t arrowLeft [] = L"<-";
+const wchar_t arrowRight[] = L"->";
 }
 
 
@@ -316,12 +319,44 @@ std::wstring zen::getCategoryDescription(CompareFilesResult cmpRes)
 
 std::wstring zen::getCategoryDescription(const FileSystemObject& fsObj)
 {
+    const std::wstring footer = L"\n[" + utfCvrtTo<std::wstring>(fsObj. getPairItemName()) + L"]";
+
     const CompareFilesResult cmpRes = fsObj.getCategory();
-    if (cmpRes == FILE_CONFLICT ||
-        cmpRes == FILE_DIFFERENT_METADATA)
-        return fsObj.getCatExtraDescription();
+    switch (cmpRes)
+    {
+        case FILE_LEFT_SIDE_ONLY:
+        case FILE_RIGHT_SIDE_ONLY:
+        case FILE_DIFFERENT_CONTENT:
+        case FILE_EQUAL:
+            return getCategoryDescription(cmpRes) + footer; //use generic description
+
+        case FILE_LEFT_NEWER:
+        case FILE_RIGHT_NEWER:
+        {
+            std::wstring descr = getCategoryDescription(cmpRes);
 
-    return getCategoryDescription(cmpRes);
+            visitFSObject(fsObj, [](const FolderPair& folder) {},
+            [&](const FilePair& file)
+            {
+                descr = descr + L"\n" +
+                        arrowLeft  + L" " + zen::utcToLocalTimeString(file.getLastWriteTime< LEFT_SIDE>()) + L"\n" +
+                        arrowRight + L" " + zen::utcToLocalTimeString(file.getLastWriteTime<RIGHT_SIDE>());
+            },
+            [&](const SymlinkPair& symlink)
+            {
+                descr = descr + L"\n" +
+                        arrowLeft  + L" " + zen::utcToLocalTimeString(symlink.getLastWriteTime< LEFT_SIDE>()) + L"\n" +
+                        arrowRight + L" " + zen::utcToLocalTimeString(symlink.getLastWriteTime<RIGHT_SIDE>());
+            });
+            return descr + footer;
+        }
+
+        case FILE_DIFFERENT_METADATA:
+        case FILE_CONFLICT:
+            return fsObj.getCatExtraDescription() + footer;
+    }
+    assert(false);
+    return std::wstring();
 }
 
 
@@ -365,6 +400,8 @@ std::wstring zen::getSyncOpDescription(SyncOperation op)
 
 std::wstring zen::getSyncOpDescription(const FileSystemObject& fsObj)
 {
+    const std::wstring footer = L"\n[" + utfCvrtTo<std::wstring>(fsObj. getPairItemName()) + L"]";
+
     const SyncOperation op = fsObj.getSyncOperation();
     switch (op)
     {
@@ -376,7 +413,7 @@ std::wstring zen::getSyncOpDescription(const FileSystemObject& fsObj)
         case SO_OVERWRITE_RIGHT:
         case SO_DO_NOTHING:
         case SO_EQUAL:
-            return getSyncOpDescription(op); //use generic description
+            return getSyncOpDescription(op) + footer; //use generic description
 
         case SO_COPY_METADATA_TO_LEFT:
         case SO_COPY_METADATA_TO_RIGHT:
@@ -389,11 +426,10 @@ std::wstring zen::getSyncOpDescription(const FileSystemObject& fsObj)
 
             if (shortNameOld != shortNameNew) //detected change in case
                 return getSyncOpDescription(op) + L"\n" +
-                       fmtPath(shortNameOld) + L" ->\n" + //show short name only
-                       fmtPath(shortNameNew);
+                       fmtPath(shortNameOld) + L" " + arrowRight + L"\n" + //show short name only
+                       fmtPath(shortNameNew) /*+ footer -> redundant */;
         }
-            //fallback:
-        return getSyncOpDescription(op);
+        return getSyncOpDescription(op) + footer; //fallback
 
         case SO_MOVE_LEFT_SOURCE:
         case SO_MOVE_LEFT_TARGET:
@@ -413,21 +449,21 @@ std::wstring zen::getSyncOpDescription(const FileSystemObject& fsObj)
                     const Zstring relSource = getRelName(*sourceFile,  onLeft);
                     const Zstring relTarget = getRelName(*targetFile, !onLeft);
 
+                    //attention: ::SetWindowText() doesn't handle tab characters correctly in combination with certain file names, so don't use them
                     return getSyncOpDescription(op) + L"\n" +
                            (equalFilePath(beforeLast(relSource, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE),
                                           beforeLast(relTarget, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE)) ?
                             //detected pure "rename"
-                            fmtPath(afterLast(relSource, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_ALL)) + L" ->\n" + //show short name only
+                            fmtPath(afterLast(relSource, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_ALL)) + L" " + arrowRight + L"\n" + //show short name only
                             fmtPath(afterLast(relTarget, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_ALL)) :
                             //"move" or "move + rename"
-                            fmtPath(relSource) + L" ->\n" +
-                            fmtPath(relTarget));
-                    //attention: ::SetWindowText() doesn't handle tab characters correctly in combination with certain file names, so don't use them
+                            fmtPath(relSource) + L" " + arrowRight + L"\n" +
+                            fmtPath(relTarget)) /*+ footer -> redundant */;
                 }
             break;
 
         case SO_UNRESOLVED_CONFLICT:
-            return fsObj.getSyncOpConflict();
+            return fsObj.getSyncOpConflict() + footer;
     }
 
     assert(false);
diff --git a/FreeFileSync/Source/fs/abstract.h b/FreeFileSync/Source/fs/abstract.h
index 302c99db..86688543 100644
--- a/FreeFileSync/Source/fs/abstract.h
+++ b/FreeFileSync/Source/fs/abstract.h
@@ -44,18 +44,22 @@ struct AbstractFileSystem //THREAD-SAFETY: "const" member functions must model t
 
     static bool isNullPath(const AbstractPath& ap) { return ap.afs->isNullPath(ap.itemPathImpl); }
 
-    static AbstractPath appendRelPath(const AbstractPath& ap, const Zstring& relPath)
+    static AbstractPath appendRelPath(const AbstractPath& ap, const Zstring& relPath);
+
+    struct PathComplement
     {
-#ifdef ZEN_WIN
-        assert(!contains(relPath, L"/")); //relPath is expected to use FILE_NAME_SEPARATOR!
-#endif
-        assert(relPath.empty() || (!startsWith(relPath, FILE_NAME_SEPARATOR) && !endsWith(relPath, FILE_NAME_SEPARATOR)));
-        return AbstractPath(ap.afs, ap.afs->appendRelPathToItemPathImpl(ap.itemPathImpl, relPath));
-    }
+        Zstring relPathL; //- relative path is filled only if the corresponding abstract path is a sub folder of the other (=> both relative paths are empty if abstract paths match)
+        Zstring relPathR; //- without FILE_NAME_SEPARATOR prefix
+    };
+    static Opt<PathComplement> getPathComplement(const AbstractPath& lhs, const AbstractPath& rhs);
 
     static Zstring getFileShortName(const AbstractPath& ap) { return ap.afs->getFileShortName(ap.itemPathImpl); }
 
-    static bool havePathDependency(const AbstractPath& lhs, const AbstractPath& rhs);
+    static bool havePathDependency(const AbstractPath& lhs, const AbstractPath& rhs)
+    {
+        warn_static("remove after migration")
+        return typeid(*lhs.afs) != typeid(*rhs.afs) ? false : lhs.afs->havePathDependencySameAfsType(lhs.itemPathImpl, rhs);
+    }
 
     static Opt<Zstring> getNativeItemPath(const AbstractPath& ap) { return ap.afs->isNativeFileSystem() ? Opt<Zstring>(ap.itemPathImpl) : NoValue(); }
 
@@ -140,9 +144,9 @@ struct AbstractFileSystem //THREAD-SAFETY: "const" member functions must model t
     private:
         std::unique_ptr<OutputStreamImpl> outStream_; //bound!
         const AbstractPath filePath_;
-        bool finalizeSucceeded = false;
-        Opt<std::uint64_t> bytesExpected;
-        std::uint64_t bytesWrittenTotal = 0;
+        bool finalizeSucceeded_ = false;
+        Opt<std::uint64_t> bytesExpected_;
+        std::uint64_t bytesWrittenTotal_ = 0;
     };
 
     //return value always bound:
@@ -278,13 +282,15 @@ private:
 
     virtual Zstring appendRelPathToItemPathImpl(const Zstring& itemPathImpl, const Zstring& relPath) const = 0;
 
+    virtual Opt<PathComplement> getPathComplementSameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const = 0;
+
+    virtual bool lessItemPathSameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const = 0;
+
     //used during folder creation if parent folder is missing
     virtual Opt<Zstring> getParentFolderPathImpl(const Zstring& itemPathImpl) const = 0;
 
     virtual Zstring getFileShortName(const Zstring& itemPathImpl) const = 0;
 
-    virtual bool lessItemPathSameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const = 0;
-
     virtual bool havePathDependencySameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const = 0;
 
     //----------------------------------------------------------------------------------------------------------------
@@ -414,12 +420,39 @@ bool AbstractFileSystem::equalAbstractPath(const AbstractPath& lhs, const Abstra
     return !LessAbstractPath()(lhs, rhs) && !LessAbstractPath()(rhs, lhs);
 }
 
+namespace impl
+{
+inline
+bool isValidRelPath(const Zstring& relPath)
+{
+#ifdef ZEN_WIN
+    const bool check1 = !contains(relPath, L'/'); //relPath is expected to use FILE_NAME_SEPARATOR!
+#elif defined ZEN_LINUX || defined ZEN_MAC
+    const bool check1 = !contains(relPath, '\\');
+#endif
+    const bool check2 = relPath.empty() || (!startsWith(relPath, FILE_NAME_SEPARATOR) && !endsWith(relPath, FILE_NAME_SEPARATOR));
+    return check1 && check2;
+}
+}
 
 inline
-bool AbstractFileSystem::havePathDependency(const AbstractPath& lhs, const AbstractPath& rhs)
+AbstractPath AbstractFileSystem::appendRelPath(const AbstractPath& ap, const Zstring& relPath)
 {
-    return typeid(*lhs.afs) != typeid(*rhs.afs) ? false : lhs.afs->havePathDependencySameAfsType(lhs.itemPathImpl, rhs);
-};
+    assert(impl::isValidRelPath(relPath));
+    return AbstractPath(ap.afs, ap.afs->appendRelPathToItemPathImpl(ap.itemPathImpl, relPath));
+}
+
+
+inline
+auto AbstractFileSystem::getPathComplement(const AbstractPath& lhs, const AbstractPath& rhs) -> Opt<PathComplement>
+{
+    if (typeid(*lhs.afs) != typeid(*rhs.afs))
+        return NoValue();
+    Opt<PathComplement> result = lhs.afs->getPathComplementSameAfsType(lhs.itemPathImpl, rhs);
+    assert(!result || (impl::isValidRelPath(result->relPathL)&& impl::isValidRelPath(result->relPathR)));
+    assert(!result || result->relPathL.empty() || result->relPathR.empty());
+    return result;
+}
 
 
 inline
@@ -452,7 +485,7 @@ AbstractFileSystem::OutputStream::OutputStream(std::unique_ptr<OutputStreamImpl>
     outStream_(std::move(outStream)), filePath_(filePath)
 {
     if (streamSize)
-        bytesExpected = *streamSize;
+        bytesExpected_ = *streamSize;
 }
 
 
@@ -463,7 +496,7 @@ AbstractFileSystem::OutputStream::~OutputStream()
 
     outStream_.reset(); //close file handle *before* remove!
 
-    if (!finalizeSucceeded) //transactional output stream! => clean up!
+    if (!finalizeSucceeded_) //transactional output stream! => clean up!
         try { AbstractFileSystem::removeFile(filePath_); /*throw FileError*/ }
         catch (FileError& e) { (void)e; assert(false); }
 }
@@ -479,7 +512,7 @@ size_t AbstractFileSystem::OutputStream::tryWrite(const void* data, size_t len)
     if (bytesWritten > len)
         throw std::logic_error("Contract violation! " + std::string(__FILE__) + ":" + numberTo<std::string>(__LINE__));
 
-    bytesWrittenTotal += bytesWritten;
+    bytesWrittenTotal_ += bytesWritten;
     return bytesWritten;
 }
 
@@ -488,14 +521,14 @@ inline
 AbstractFileSystem::FileId AbstractFileSystem::OutputStream::finalize(const std::function<void()>& onUpdateStatus) //throw FileError
 {
     //important check: catches corrupt sftp download with libssh2!
-    if (bytesExpected && *bytesExpected != bytesWrittenTotal)
+    if (bytesExpected_ && *bytesExpected_ != bytesWrittenTotal_)
         throw FileError(replaceCpy(_("Cannot write file %x."), L"%x", fmtPath(getDisplayPath(filePath_))),
                         replaceCpy(replaceCpy(_("Unexpected size of data stream.\nExpected: %x bytes\nActual: %y bytes"),
-                                              L"%x", numberTo<std::wstring>(*bytesExpected)),
-                                   L"%y", numberTo<std::wstring>(bytesWrittenTotal)));
+                                              L"%x", numberTo<std::wstring>(*bytesExpected_)),
+                                   L"%y", numberTo<std::wstring>(bytesWrittenTotal_)));
 
     FileId fileId = outStream_->finalize(onUpdateStatus); //throw FileError
-    finalizeSucceeded = true;
+    finalizeSucceeded_ = true;
     return fileId;
 }
 
diff --git a/FreeFileSync/Source/fs/native.cpp b/FreeFileSync/Source/fs/native.cpp
index 994d3388..9c341769 100644
--- a/FreeFileSync/Source/fs/native.cpp
+++ b/FreeFileSync/Source/fs/native.cpp
@@ -264,6 +264,24 @@ private:
 
     Zstring appendRelPathToItemPathImpl(const Zstring& itemPathImpl, const Zstring& relPath) const override { return appendPaths(itemPathImpl, relPath, FILE_NAME_SEPARATOR); }
 
+    Opt<PathComplement> getPathComplementSameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const override
+    {
+        const Zstring& lhs = appendSeparator(itemPathImplLhs);
+        const Zstring& rhs = appendSeparator(getItemPathImpl(apRhs));
+
+        const size_t lenMin = std::min(lhs.length(), rhs.length());
+
+        if (cmpFilePath(lhs.c_str(), lenMin,
+                        rhs.c_str(), lenMin) != 0)
+            return NoValue();
+
+        return PathComplement({ Zstring(lhs.begin() + lenMin, lhs.end()),
+                                Zstring(rhs.begin() + lenMin, rhs.end())
+                              });
+    }
+
+    bool lessItemPathSameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const override { return LessFilePath()(itemPathImplLhs, getItemPathImpl(apRhs)); }
+
     //used during folder creation if parent folder is missing
     Opt<Zstring> getParentFolderPathImpl(const Zstring& itemPathImpl) const override
     {
@@ -292,8 +310,6 @@ private:
 
     Zstring getFileShortName(const Zstring& itemPathImpl) const override { return afterLast(itemPathImpl, FILE_NAME_SEPARATOR, IF_MISSING_RETURN_ALL); }
 
-    bool lessItemPathSameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const override { return LessFilePath()(itemPathImplLhs, getItemPathImpl(apRhs)); }
-
     bool havePathDependencySameAfsType(const Zstring& itemPathImplLhs, const AbstractPath& apRhs) const override
     {
         const Zstring& lhs = appendSeparator(itemPathImplLhs);
diff --git a/FreeFileSync/Source/fs/native_traverser_impl.h b/FreeFileSync/Source/fs/native_traverser_impl.h
index dedc5c61..35891c8a 100644
--- a/FreeFileSync/Source/fs/native_traverser_impl.h
+++ b/FreeFileSync/Source/fs/native_traverser_impl.h
@@ -77,7 +77,7 @@ private:
         {
             struct ::dirent* dirEntry = nullptr;
             if (::readdir_r(dirObj, reinterpret_cast< ::dirent*>(&buffer[0]), &dirEntry) != 0)
-                THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot enumerate directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r");
+                THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r");
             //don't retry but restart dir traversal on error! http://blogs.msdn.com/b/oldnewthing/archive/2014/06/12/10533529.aspx
 
             if (!dirEntry) //no more items
@@ -86,7 +86,7 @@ private:
             //don't return "." and ".."
             const char* itemName = dirEntry->d_name; //evaluate dirEntry *before* going into recursion => we use a single "buffer"!
 
-            if (itemName[0] == 0) throw FileError(replaceCpy(_("Cannot enumerate directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r: Data corruption; item is missing a name.");
+            if (itemName[0] == 0) throw FileError(replaceCpy(_("Cannot read directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r: Data corruption; item is missing a name.");
             if (itemName[0] == '.' &&
                 (itemName[1] == 0 || (itemName[1] == '.' && itemName[2] == 0)))
                 continue;
diff --git a/FreeFileSync/Source/lib/binary.cpp b/FreeFileSync/Source/lib/binary.cpp
index 38fc0fda..0d9b9549 100644
--- a/FreeFileSync/Source/lib/binary.cpp
+++ b/FreeFileSync/Source/lib/binary.cpp
@@ -39,22 +39,22 @@ const size_t BLOCK_SIZE_MAX =  16 * 1024 * 1024;
 struct StreamReader
 {
     StreamReader(const AbstractPath& filePath, const std::function<void(std::int64_t bytesDelta)>& notifyProgress, size_t& unevenBytes) :
-        stream(AFS::getInputStream(filePath)), //throw FileError, (ErrorFileLocked)
-        defaultBlockSize(stream->getBlockSize()),
-        dynamicBlockSize(defaultBlockSize),
+        stream_(AFS::getInputStream(filePath)), //throw FileError, (ErrorFileLocked)
+        defaultBlockSize_(stream_->getBlockSize()),
+        dynamicBlockSize_(defaultBlockSize_),
         notifyProgress_(notifyProgress),
         unevenBytes_(unevenBytes) {}
 
     void appendChunk(std::vector<char>& buffer) //throw FileError
     {
-        assert(!eof);
-        if (eof) return;
+        assert(!eof_);
+        if (eof_) return;
 
         const auto startTime = std::chrono::steady_clock::now();
 
-        buffer.resize(buffer.size() + dynamicBlockSize);
-        const size_t bytesRead = stream->tryRead(&*(buffer.end() - dynamicBlockSize), dynamicBlockSize); //throw FileError; may return short, only 0 means EOF! => CONTRACT: bytesToRead > 0
-        buffer.resize(buffer.size() - dynamicBlockSize + bytesRead); //caveat: unsigned arithmetics
+        buffer.resize(buffer.size() + dynamicBlockSize_);
+        const size_t bytesRead = stream_->tryRead(&*(buffer.end() - dynamicBlockSize_), dynamicBlockSize_); //throw FileError; may return short, only 0 means EOF! => CONTRACT: bytesToRead > 0
+        buffer.resize(buffer.size() - dynamicBlockSize_ + bytesRead); //caveat: unsigned arithmetics
 
         const auto stopTime = std::chrono::steady_clock::now();
 
@@ -68,7 +68,7 @@ struct StreamReader
 
         if (bytesRead == 0)
         {
-            eof = true;
+            eof_ = true;
             return;
         }
 
@@ -76,31 +76,31 @@ struct StreamReader
         const auto loopTimeMs = std::chrono::duration_cast<std::chrono::milliseconds>(stopTime - startTime).count();
 
         if (loopTimeMs >= 100)
-            lastDelayViolation = stopTime;
+            lastDelayViolation_ = stopTime;
 
         //avoid "flipping back": e.g. DVD-ROMs read 32MB at once, so first read may be > 500 ms, but second one will be 0ms!
-        if (stopTime >= lastDelayViolation + std::chrono::seconds(2))
+        if (stopTime >= lastDelayViolation_ + std::chrono::seconds(2))
         {
-            lastDelayViolation = stopTime;
-            proposedBlockSize = dynamicBlockSize * 2;
+            lastDelayViolation_ = stopTime;
+            proposedBlockSize = dynamicBlockSize_ * 2;
         }
         if (loopTimeMs > 500)
-            proposedBlockSize = dynamicBlockSize / 2;
+            proposedBlockSize = dynamicBlockSize_ / 2;
 
-        if (defaultBlockSize <= proposedBlockSize && proposedBlockSize <= BLOCK_SIZE_MAX)
-            dynamicBlockSize = proposedBlockSize;
+        if (defaultBlockSize_ <= proposedBlockSize && proposedBlockSize <= BLOCK_SIZE_MAX)
+            dynamicBlockSize_ = proposedBlockSize;
     }
 
-    bool isEof() const { return eof; }
+    bool isEof() const { return eof_; }
 
 private:
-    const std::unique_ptr<AFS::InputStream> stream;
-    const size_t defaultBlockSize;
-    size_t dynamicBlockSize;
+    const std::unique_ptr<AFS::InputStream> stream_;
+    const size_t defaultBlockSize_;
+    size_t dynamicBlockSize_;
     const std::function<void(std::int64_t bytesDelta)> notifyProgress_;
     size_t& unevenBytes_;
-    std::chrono::steady_clock::time_point lastDelayViolation = std::chrono::steady_clock::now();
-    bool eof = false;
+    std::chrono::steady_clock::time_point lastDelayViolation_ = std::chrono::steady_clock::now();
+    bool eof_ = false;
 };
 }
 
diff --git a/FreeFileSync/Source/lib/db_file.cpp b/FreeFileSync/Source/lib/db_file.cpp
index 7fb7977e..ea679635 100644
--- a/FreeFileSync/Source/lib/db_file.cpp
+++ b/FreeFileSync/Source/lib/db_file.cpp
@@ -141,11 +141,11 @@ DbStreams loadStreams(const AbstractPath& dbPath, const std::function<void(std::
     }
     catch (UnexpectedEndOfStreamError&)
     {
-        throw FileError(_("Database file is corrupt:") + L"\n" + fmtPath(AFS::getDisplayPath(dbPath)), L"Unexpected end of stream.");
+        throw FileError(_("Database file is corrupted:") + L"\n" + fmtPath(AFS::getDisplayPath(dbPath)), L"Unexpected end of stream.");
     }
     catch (const std::bad_alloc& e) //still required?
     {
-        throw FileError(_("Database file is corrupt:") + L"\n" + fmtPath(AFS::getDisplayPath(dbPath)),
+        throw FileError(_("Database file is corrupted:") + L"\n" + fmtPath(AFS::getDisplayPath(dbPath)),
                         _("Out of memory.") + L" " + utfCvrtTo<std::wstring>(e.what()));
     }
 }
@@ -305,7 +305,7 @@ public:
             const int streamVersionR = readNumber<std::int32_t>(inR); //
 
             if (streamVersionL != streamVersionR)
-                throw FileError(_("Database file is corrupt:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR), L"different stream formats");
+                throw FileError(_("Database file is corrupted:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR), L"different stream formats");
 
             if (streamVersionL != DB_FORMAT_STREAM)
                 throw FileError(replaceCpy(_("Database file %x is incompatible."), L"%x", fmtPath(displayFilePathL)), L"unknown stream format");
@@ -314,7 +314,7 @@ public:
             const bool has1stPartR = readNumber<std::int8_t>(inR) != 0; //
 
             if (has1stPartL == has1stPartR)
-                throw FileError(_("Database file is corrupt:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR), L"second part missing");
+                throw FileError(_("Database file is corrupted:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR), L"second part missing");
 
             MemStreamIn& in1stPart = has1stPartL ? inL : inR;
             MemStreamIn& in2ndPart = has1stPartL ? inR : inL;
@@ -340,11 +340,11 @@ public:
         }
         catch (const UnexpectedEndOfStreamError&)
         {
-            throw FileError(_("Database file is corrupt:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR), L"Unexpected end of stream.");
+            throw FileError(_("Database file is corrupted:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR), L"Unexpected end of stream.");
         }
         catch (const std::bad_alloc& e)
         {
-            throw FileError(_("Database file is corrupt:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR),
+            throw FileError(_("Database file is corrupted:") + L"\n" + fmtPath(displayFilePathL) + L"\n" + fmtPath(displayFilePathR),
                             _("Out of memory.") + L" " + utfCvrtTo<std::wstring>(e.what()));
         }
     }
diff --git a/FreeFileSync/Source/lib/dir_exist_async.h b/FreeFileSync/Source/lib/dir_exist_async.h
index d3eaa9c1..d790404e 100644
--- a/FreeFileSync/Source/lib/dir_exist_async.h
+++ b/FreeFileSync/Source/lib/dir_exist_async.h
@@ -10,6 +10,7 @@
 #include <list>
 #include <zen/thread.h>
 #include <zen/file_error.h>
+#include <zen/basic_math.h>
 #include "../fs/abstract.h"
 #include "../process_callback.h"
 
@@ -49,7 +50,7 @@ FolderStatus getFolderStatusNonBlocking(const std::set<AbstractPath, AFS::LessAb
         }));
 
     //don't wait (almost) endlessly like Win32 would on non-existing network shares:
-    std::chrono::steady_clock::time_point stopTime = std::chrono::steady_clock::now() + std::chrono::seconds(folderAccessTimeout);
+    const auto startTime = std::chrono::steady_clock::now();
 
     for (auto& fi : futureInfo)
     {
@@ -57,8 +58,8 @@ FolderStatus getFolderStatusNonBlocking(const std::set<AbstractPath, AFS::LessAb
 
         procCallback.reportStatus(replaceCpy(_("Searching for folder %x..."), L"%x", displayPathFmt)); //may throw!
 
-        while (std::chrono::steady_clock::now() < stopTime &&
-               fi.second.wait_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL / 2)) != std::future_status::ready)
+        while (numeric::dist(std::chrono::steady_clock::now(), startTime) < std::chrono::seconds(folderAccessTimeout) && //handle potential chrono wrap-around!
+               fi.second.wait_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS / 2)) != std::future_status::ready)
             procCallback.requestUiRefresh(); //may throw!
 
         if (isReady(fi.second))
diff --git a/FreeFileSync/Source/lib/dir_lock.cpp b/FreeFileSync/Source/lib/dir_lock.cpp
index 6a8960ca..e2184781 100644
--- a/FreeFileSync/Source/lib/dir_lock.cpp
+++ b/FreeFileSync/Source/lib/dir_lock.cpp
@@ -364,12 +364,12 @@ std::string retrieveLockId(const Zstring& lockFilePath) //throw FileError
 }
 
 
-enum ProcessStatus
+enum class ProcessStatus
 {
-    PROC_STATUS_NOT_RUNNING,
-    PROC_STATUS_RUNNING,
-    PROC_STATUS_ITS_US,
-    PROC_STATUS_CANT_TELL
+    NOT_RUNNING,
+    RUNNING,
+    ITS_US,
+    CANT_TELL,
 };
 
 ProcessStatus getProcessStatus(const LockInformation& lockInfo) //throw FileError
@@ -378,15 +378,15 @@ ProcessStatus getProcessStatus(const LockInformation& lockInfo) //throw FileErro
 
     if (lockInfo.computerName != localInfo.computerName ||
         lockInfo.userId != localInfo.userId) //another user may run a session right now!
-        return PROC_STATUS_CANT_TELL; //lock owned by different computer in this network
+        return ProcessStatus::CANT_TELL; //lock owned by different computer in this network
 
     if (lockInfo.sessionId == localInfo.sessionId &&
         lockInfo.processId == localInfo.processId) //obscure, but possible: deletion failed or a lock file is "stolen" and put back while the program is running
-        return PROC_STATUS_ITS_US;
+        return ProcessStatus::ITS_US;
 
     if (Opt<SessionId> sessionId = getSessionId(lockInfo.processId)) //throw FileError
-        return *sessionId == lockInfo.sessionId ? PROC_STATUS_RUNNING : PROC_STATUS_NOT_RUNNING;
-    return PROC_STATUS_NOT_RUNNING;
+        return *sessionId == lockInfo.sessionId ? ProcessStatus::RUNNING : ProcessStatus::NOT_RUNNING;
+    return ProcessStatus::NOT_RUNNING;
 }
 
 
@@ -412,12 +412,12 @@ void waitOnDirLock(const Zstring& lockFilePath, DirLockCallback* callback) //thr
             originalLockId = lockInfo.lockId;
             switch (getProcessStatus(lockInfo)) //throw FileError
             {
-                case PROC_STATUS_ITS_US: //since we've already passed LockAdmin, the lock file seems abandoned ("stolen"?) although it's from this process
-                case PROC_STATUS_NOT_RUNNING:
+                case ProcessStatus::ITS_US: //since we've already passed LockAdmin, the lock file seems abandoned ("stolen"?) although it's from this process
+                case ProcessStatus::NOT_RUNNING:
                     lockOwnderDead = true;
                     break;
-                case PROC_STATUS_RUNNING:
-                case PROC_STATUS_CANT_TELL:
+                case ProcessStatus::RUNNING:
+                case ProcessStatus::CANT_TELL:
                     break;
             }
         }
diff --git a/FreeFileSync/Source/lib/error_log.h b/FreeFileSync/Source/lib/error_log.h
index bef4a75d..3241803e 100644
--- a/FreeFileSync/Source/lib/error_log.h
+++ b/FreeFileSync/Source/lib/error_log.h
@@ -34,7 +34,7 @@ void logFatalError(const std::string& msg) //throw()
     const std::string logEntry = "[" + formatTime<std::string>(FORMAT_DATE) + " "+ formatTime<std::string>(FORMAT_TIME) + "] " + msg;
     try
     {
-        saveBinContainer(getConfigDir() + Zstr("LastError.log"), logEntry, nullptr); //throw FileError
+        saveBinContainer(getConfigDirPathPf() + Zstr("LastError.log"), logEntry, nullptr); //throw FileError
     }
     catch (const FileError&) {}
 }
diff --git a/FreeFileSync/Source/lib/ffs_paths.cpp b/FreeFileSync/Source/lib/ffs_paths.cpp
index 9df9ce5e..f57409d8 100644
--- a/FreeFileSync/Source/lib/ffs_paths.cpp
+++ b/FreeFileSync/Source/lib/ffs_paths.cpp
@@ -30,22 +30,22 @@ Zstring getExecutablePathPf() //directory containing executable WITH path separa
     return appendSeparator(beforeLast(utfCvrtTo<Zstring>(wxStandardPaths::Get().GetExecutablePath()), FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE));
 }
 #endif
+}
+
 
 #ifdef ZEN_WIN
-inline
-Zstring getInstallFolderPathPf() //root install directory WITH path separator at end
+Zstring zen::getInstallDirPath() //root install directory WITHOUT path separator at end
 {
-    return appendSeparator(beforeLast(beforeLast(getExecutablePathPf(), FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE), FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE));
+    return beforeLast(beforeLast(getExecutablePathPf(), FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE), FILE_NAME_SEPARATOR, IF_MISSING_RETURN_NONE);
 }
 #endif
-}
 
 
 bool zen::isPortableVersion()
 {
 #ifdef ZEN_WIN
-    return !fileExists(getInstallFolderPathPf() + L"uninstall.exe") && //created by NSIS
-           !dirExists (getInstallFolderPathPf() + L"Uninstall");       //created by Inno Setup
+    return !fileExists(appendSeparator(getInstallDirPath()) + L"uninstall.exe") && //created by NSIS
+           !dirExists (appendSeparator(getInstallDirPath()) + L"Uninstall");       //created by Inno Setup
 
 #elif defined ZEN_LINUX
     return !endsWith(getExecutablePathPf(), "/bin/");  //this check is a bit lame...
@@ -56,18 +56,7 @@ bool zen::isPortableVersion()
 }
 
 
-bool zen::manualProgramUpdateRequired()
-{
-#if defined ZEN_WIN || defined ZEN_MAC
-    return true;
-#elif defined ZEN_LINUX
-    return true;
-    //return isPortableVersion(); //locally installed version is updated by Launchpad
-#endif
-}
-
-
-Zstring zen::getResourceDir()
+Zstring zen::getResourceDirPf()
 {
     //make independent from wxWidgets global variable "appname"; support being called by RealTimeSync
     auto appName = wxTheApp->GetAppName();
@@ -75,7 +64,7 @@ Zstring zen::getResourceDir()
     ZEN_ON_SCOPE_EXIT(wxTheApp->SetAppName(appName));
 
 #ifdef ZEN_WIN
-    return getInstallFolderPathPf();
+    return appendSeparator(getInstallDirPath());
 #elif defined ZEN_LINUX
     if (isPortableVersion())
         return getExecutablePathPf();
@@ -87,7 +76,7 @@ Zstring zen::getResourceDir()
 }
 
 
-Zstring zen::getConfigDir()
+Zstring zen::getConfigDirPathPf()
 {
     //make independent from wxWidgets global variable "appname"; support being called by RealTimeSync
     auto appName = wxTheApp->GetAppName();
@@ -96,7 +85,7 @@ Zstring zen::getConfigDir()
 
 #ifdef ZEN_WIN
     if (isPortableVersion())
-        return getInstallFolderPathPf();
+        return appendSeparator(getInstallDirPath());
 #elif defined ZEN_LINUX
     if (isPortableVersion())
         return getExecutablePathPf();
@@ -119,7 +108,7 @@ Zstring zen::getConfigDir()
 Zstring zen::getFreeFileSyncLauncherPath()
 {
 #ifdef ZEN_WIN
-    return getInstallFolderPathPf() + Zstr("FreeFileSync.exe");
+    return appendSeparator(getInstallDirPath()) + Zstr("FreeFileSync.exe");
 
 #elif defined ZEN_LINUX
     return getExecutablePathPf() + Zstr("FreeFileSync");
diff --git a/FreeFileSync/Source/lib/ffs_paths.h b/FreeFileSync/Source/lib/ffs_paths.h
index 497681c1..2fe32220 100644
--- a/FreeFileSync/Source/lib/ffs_paths.h
+++ b/FreeFileSync/Source/lib/ffs_paths.h
@@ -14,14 +14,17 @@ namespace zen
 //------------------------------------------------------------------------------
 //global program directories
 //------------------------------------------------------------------------------
-Zstring getResourceDir(); //resource directory WITH path separator at end
-Zstring getConfigDir  (); //config directory WITH path separator at end
+Zstring getResourceDirPf(); //resource directory WITH path separator at end
+Zstring getConfigDirPathPf  (); //config directory WITH path separator at end
 //------------------------------------------------------------------------------
 
 bool isPortableVersion();
 
+#ifdef ZEN_WIN
+    Zstring getInstallDirPath(); //root install directory WITHOUT path separator at end
+#endif
+
 Zstring getFreeFileSyncLauncherPath(); //full path to application launcher C:\...\FreeFileSync.exe
-bool manualProgramUpdateRequired();
 }
 
 #endif //FFS_PATHS_H_842759083425342534253
diff --git a/FreeFileSync/Source/lib/generate_logfile.h b/FreeFileSync/Source/lib/generate_logfile.h
index 9b463426..ff85d2f7 100644
--- a/FreeFileSync/Source/lib/generate_logfile.h
+++ b/FreeFileSync/Source/lib/generate_logfile.h
@@ -12,6 +12,7 @@
 #include <zen/format_unit.h>
 #include "ffs_paths.h"
 #include "../fs/abstract.h"
+#include "../file_hierarchy.h"
 
 
 namespace zen
@@ -152,7 +153,7 @@ void streamToLogFile(const SummaryInfo& summary, //throw FileError
 
 
 inline
-Zstring getLastSyncsLogfilePath() { return getConfigDir() + Zstr("LastSyncs.log"); }
+Zstring getLastSyncsLogfilePath() { return getConfigDirPathPf() + Zstr("LastSyncs.log"); }
 
 
 inline
diff --git a/FreeFileSync/Source/lib/hard_filter.cpp b/FreeFileSync/Source/lib/hard_filter.cpp
index 36ad6871..6bef6e11 100644
--- a/FreeFileSync/Source/lib/hard_filter.cpp
+++ b/FreeFileSync/Source/lib/hard_filter.cpp
@@ -110,11 +110,13 @@ const Char* cStringFind(const Char* str, Char ch) //= strchr(), wcschr()
 }
 
 
+/*
 struct FullMatch
 {
     static bool matchesMaskEnd (const Zchar* path) { return *path == 0; }
     static bool matchesMaskStar(const Zchar* path) { return true; }
 };
+*/
 
 struct ParentFolderMatch //strict match of parent folder path!
 {
@@ -250,8 +252,6 @@ std::vector<Zstring> zen::splitByDelimiter(const Zstring& filterString)
 
 NameFilter::NameFilter(const Zstring& includePhrase, const Zstring& excludePhrase)
 {
-    //no need for regular expressions: In tests wxRegex was slower than wxString::Matches() by a factor of 10
-
     //setup include/exclude filters for files and directories
     for (const Zstring& entry : splitByDelimiter(includePhrase)) addFilterEntry(entry, includeMasksFileFolder, includeMasksFolder);
     for (const Zstring& entry : splitByDelimiter(excludePhrase)) addFilterEntry(entry, excludeMasksFileFolder, excludeMasksFolder);
@@ -274,6 +274,7 @@ void NameFilter::addExclusion(const Zstring& excludePhrase)
 
 bool NameFilter::passFileFilter(const Zstring& relFilePath) const
 {
+    assert(!startsWith(relFilePath, FILE_NAME_SEPARATOR));
 #if defined ZEN_WIN || defined ZEN_MAC //Windows does NOT distinguish between upper/lower-case
     const Zstring& pathFmt = makeUpperCopy(relFilePath);
 #elif defined ZEN_LINUX //Linux DOES distinguish between upper/lower-case
@@ -291,6 +292,7 @@ bool NameFilter::passFileFilter(const Zstring& relFilePath) const
 
 bool NameFilter::passDirFilter(const Zstring& relDirPath, bool* childItemMightMatch) const
 {
+    assert(!startsWith(relDirPath, FILE_NAME_SEPARATOR));
     assert(!childItemMightMatch || *childItemMightMatch == true); //check correct usage
 
 #if defined ZEN_WIN || defined ZEN_MAC //Windows does NOT distinguish between upper/lower-case
@@ -306,8 +308,8 @@ bool NameFilter::passDirFilter(const Zstring& relDirPath, bool* childItemMightMa
             *childItemMightMatch = false; //perf: no need to traverse deeper; subfolders/subfiles would be excluded by filter anyway!
         /*
         Attention: the design choice that "childItemMightMatch" is optional implies that the filter must provide correct results no matter if this
-        value is considered by the client! In particular, if *childItemMightMatch == false, then any filter evaluations for child items must
-        also return "false"!
+        value is considered by the client!
+        In particular, if *childItemMightMatch == false, then any filter evaluations for child items must also return "false"!
         This is not a problem for folder traversal which stops at the first *childItemMightMatch == false anyway, but other code continues recursing further,
         e.g. the database update code in db_file.cpp recurses unconditionally without filter check! It's possible to construct edge cases with incorrect
         behavior if "childItemMightMatch" were not optional:
diff --git a/FreeFileSync/Source/lib/help_provider.h b/FreeFileSync/Source/lib/help_provider.h
index a42995be..67e1c34e 100644
--- a/FreeFileSync/Source/lib/help_provider.h
+++ b/FreeFileSync/Source/lib/help_provider.h
@@ -15,22 +15,20 @@ inline void uninitializeHelp() {}
 }
 
 #else
+#include <zen/globals.h>
+#include <wx+/http.h>
+#include "ffs_paths.h"
+
 #ifdef ZEN_WIN
-    #include <zen/zstring.h>
     #include <wx/msw/helpchm.h>
-
 #elif defined ZEN_LINUX || defined ZEN_MAC
     #include <wx/html/helpctrl.h>
 #endif
 
-#include "ffs_paths.h"
-
 
 namespace zen
 {
-void displayHelpEntry(wxWindow* parent);
 void displayHelpEntry(const wxString& topic, wxWindow* parent);
-
 void uninitializeHelp(); //clean up gracefully during app shutdown: leaving this up to static destruction crashes on Win 8.1!
 
 
@@ -41,68 +39,29 @@ void uninitializeHelp(); //clean up gracefully during app shutdown: leaving this
 //######################## implementation ########################
 namespace impl
 {
-//finish wxWidgets' job:
 #ifdef ZEN_WIN
-class FfsHelpController
+class FfsHelpController //finish wxWidgets' job:
 {
 public:
-    static FfsHelpController& instance()
-    {
-        static FfsHelpController inst; //external linkage, despite inline definition!
-        return inst;
-    }
+    FfsHelpController () { chmHlp.Initialize(utfCvrtTo<wxString>(zen::getResourceDirPf()) + L"FreeFileSync.chm"); }
+    ~FfsHelpController() { chmHlp.Quit(); } //don't keep help window open while app is shut down! => crash on Win 8.1!
 
-    void openSection(const wxString& section, wxWindow* parent)
+    void displaySection(const wxString& section)
     {
-        //don't put in constructor: not needed if only uninitialize() is ever called!
-        if (!chmHlp)
-        {
-            chmHlp = std::make_unique<wxCHMHelpController>();
-            chmHlp->Initialize(utfCvrtTo<wxString>(zen::getResourceDir()) + L"FreeFileSync.chm");
-        }
-
-        if (section.empty())
-            chmHlp->DisplayContents();
-        else
-            chmHlp->DisplaySection(replaceCpy(section, L'/', utfCvrtTo<wxString>(FILE_NAME_SEPARATOR)));
-    }
-
-    void uninitialize() //avoid static init/teardown order fiasco
-    {
-        if (chmHlp)
-        {
-            chmHlp->Quit(); //don't let help windows open while app is shut down! => crash on Win 8.1!
-            chmHlp.reset();
-        }
+        chmHlp.DisplaySection(replaceCpy(section, L'/', FILE_NAME_SEPARATOR));
     }
 
 private:
-    FfsHelpController() {}
-    ~FfsHelpController() { assert(!chmHlp); }
-
-    std::unique_ptr<wxCHMHelpController> chmHlp;
+    wxCHMHelpController chmHlp;
 };
 
-#elif defined ZEN_LINUX || defined ZEN_MAC
-struct FfsHelpController
-{
-    static FfsHelpController& instance()
-    {
-        static FfsHelpController inst;
-        return inst;
-    }
 
-    void openSection(const wxString& section, wxWindow* parent)
-    {
-        wxHtmlModalHelp dlg(parent, utfCvrtTo<wxString>(zen::getResourceDir()) + L"Help/FreeFileSync.hhp", section,
-                            wxHF_DEFAULT_STYLE | wxHF_DIALOG | wxHF_MODAL | wxHF_MERGE_BOOKS);
-        (void)dlg;
-        //-> solves modal help craziness on OSX!
-        //-> Suse Linux: avoids program hang on exit if user closed help parent dialog before the help dialog itself was closed (why is this even possible???)
-        //               avoids ESC key not being recognized by help dialog (but by parent dialog instead)
-    }
-    void uninitialize() {}
-};
+inline
+Global<FfsHelpController>& refGlobalHelpController()
+{
+    static Global<FfsHelpController> inst(std::make_unique<FfsHelpController>()); //external linkage even in header!
+    return inst;
+}
 #endif
 }
 
@@ -110,21 +69,35 @@ struct FfsHelpController
 inline
 void displayHelpEntry(const wxString& topic, wxWindow* parent)
 {
-    impl::FfsHelpController::instance().openSection(L"html/" + topic + L".html", parent);
-}
+    if (internetIsAlive()) //noexcept
+        wxLaunchDefaultBrowser(L"http://www.freefilesync.org/manual.php?topic=" + topic);
+    else
+        -> what if FFS is blocked, but the web browser would have internet access??
+    {
+        const wxString section = L"html/" + topic + L".html";
+#ifdef ZEN_WIN
+        if (std::shared_ptr<impl::FfsHelpController> h = impl::refGlobalHelpController().get())
+                h->displaySection(section);
 
+#elif defined ZEN_LINUX || defined ZEN_MAC
+        wxHtmlModalHelp dlg(parent, utfCvrtTo<wxString>(zen::getResourceDirPf()) + L"Help/FreeFileSync.hhp", section,
+        wxHF_DEFAULT_STYLE | wxHF_DIALOG | wxHF_MODAL | wxHF_MERGE_BOOKS);
+            (void)dlg;
+            //-> solves modal help craziness on OSX!
+            //-> Suse Linux: avoids program hang on exit if user closed help parent dialog before the help dialog itself was closed (why is this even possible???)
+            //               avoids ESC key not being recognized by help dialog (but by parent dialog instead)
 
-inline
-void displayHelpEntry(wxWindow* parent)
-{
-    impl::FfsHelpController::instance().openSection(wxString(), parent);
+#endif
+        }
 }
 
+
 inline
 void uninitializeHelp()
 {
-    impl::FfsHelpController::instance().uninitialize();
-
+#ifdef ZEN_WIN
+    impl::refGlobalHelpController().set(nullptr);
+#endif
 }
 }
 #endif
diff --git a/FreeFileSync/Source/lib/icon_buffer.cpp b/FreeFileSync/Source/lib/icon_buffer.cpp
index 91f6f68f..10965397 100644
--- a/FreeFileSync/Source/lib/icon_buffer.cpp
+++ b/FreeFileSync/Source/lib/icon_buffer.cpp
@@ -29,10 +29,6 @@ const size_t BUFFER_SIZE_MAX = 800; //maximum number of icons to hold in buffer:
     const std::thread::id mainThreadId = std::this_thread::get_id();
 #endif
 
-#ifdef ZEN_WIN
-    const bool wereVistaOrLater = vistaOrLater();
-#endif
-
 
 //destroys raw icon! Call from GUI thread only!
 wxBitmap extractWxBitmap(ImageHolder&& ih)
@@ -333,14 +329,14 @@ public:
                  IconBuffer::IconSize st) :
         workload_(workload),
         buffer_(buffer),
-        iconSizeType(st) {}
+        iconSizeType_(st) {}
 
     void operator()() const; //thread entry
 
 private:
     std::shared_ptr<WorkLoad> workload_; //main/worker thread may access different shared_ptr instances safely (even though they have the same target!)
     std::shared_ptr<Buffer> buffer_;     //http://www.boost.org/doc/libs/1_43_0/libs/smart_ptr/shared_ptr.htm?sess=8153b05b34d890e02d48730db1ff7ddc#ThreadSafety
-    const IconBuffer::IconSize iconSizeType;
+    const IconBuffer::IconSize iconSizeType_;
 };
 
 
@@ -370,13 +366,11 @@ void WorkerThread::operator()() const //thread entry
 {
 #ifdef ZEN_WIN
     setCurrentThreadName("Icon Buffer Worker");
-
     try
     {
-        //1. Initialize COM here due to the icon_loader.h dependency only, but NOT due to native.h, mtp.h's internal COM usage => this is not our responsibility!
+        //1. Initialize COM here only due to the icon_loader.h dependency, but NOT due to native.h, mtp.h's internal COM usage => this is not our responsibility!
         ComInitializer ci; //throw SysError
 #endif
-
         for (;;)
         {
             interruptionPoint(); //throw ThreadInterruption
@@ -385,7 +379,7 @@ void WorkerThread::operator()() const //thread entry
             const AbstractPath itemPath = workload_->extractNextFile(); //throw ThreadInterruption
 
             if (!buffer_->hasIcon(itemPath)) //perf: workload may contain duplicate entries?
-                buffer_->insert(itemPath, getDisplayIcon(itemPath, iconSizeType));
+                buffer_->insert(itemPath, getDisplayIcon(itemPath, iconSizeType_));
         }
 
 #ifdef ZEN_WIN
@@ -404,7 +398,7 @@ struct IconBuffer::Impl
     InterruptibleThread worker;
 
     //-------------------------
-    std::map<Zstring, wxBitmap, LessFilePath> extensionIcons;
+    std::map<Zstring, wxBitmap, LessFilePath> extensionIcons; //no item count limit!? Test case C:\ ~ 3800 unique file extensions
 };
 
 
@@ -434,11 +428,11 @@ int IconBuffer::getSize(IconSize sz)
             return 24;
 #endif
         case IconBuffer::SIZE_MEDIUM:
-#ifdef ZEN_WIN
-            if (!wereVistaOrLater) return 32; //48x48 doesn't look sharp on XP
-#endif
+#ifdef ZEN_WIN_PRE_VISTA
+            return 32; //48x48 doesn't look sharp on XP
+#else //Win (Vista) or Linux/Mac
             return 48;
-
+#endif
         case IconBuffer::SIZE_LARGE:
             return 128;
     }
@@ -467,7 +461,6 @@ Opt<wxBitmap> IconBuffer::retrieveFileIcon(const AbstractPath& filePath)
         if (hasStandardIconExtension(fileName))
             return this->getIconByExtension(fileName); //buffered!!!
 #endif
-
     if (Opt<wxBitmap> ico = pimpl->buffer->retrieve(filePath))
         return ico;
 
@@ -489,17 +482,17 @@ void IconBuffer::setWorkload(const std::vector<AbstractPath>& load)
 
 wxBitmap IconBuffer::getIconByExtension(const Zstring& filePath)
 {
-    const Zstring& extension = getFileExtension(filePath);
+    const Zstring& ext = getFileExtension(filePath);
 
     assert(std::this_thread::get_id() == mainThreadId);
 
-    auto it = pimpl->extensionIcons.find(extension);
+    auto it = pimpl->extensionIcons.find(ext);
     if (it == pimpl->extensionIcons.end())
     {
-        const Zstring& templateName(extension.empty() ? Zstr("file") : Zstr("file.") + extension);
+        const Zstring& templateName(ext.empty() ? Zstr("file") : Zstr("file.") + ext);
         //don't pass actual file name to getIconByTemplatePath(), e.g. "AUTHORS" has own mime type on Linux!!!
         //=> we want to buffer by extension only to minimize buffer-misses!
-        it = pimpl->extensionIcons.emplace(extension, extractWxBitmap(getIconByTemplatePath(templateName, IconBuffer::getSize(iconSizeType)))).first;
+        it = pimpl->extensionIcons.emplace(ext, extractWxBitmap(getIconByTemplatePath(templateName, IconBuffer::getSize(iconSizeType)))).first;
     }
     //need buffer size limit???
     return it->second;
@@ -527,7 +520,9 @@ wxBitmap IconBuffer::linkOverlayIcon(IconSize sz)
 
         if (pixelSize >= 128) return L"link_128";
         if (pixelSize >=  48) return L"link_48";
+#ifdef ZEN_WIN_PRE_VISTA
         if (pixelSize >=  32) return L"link_32";
+#endif
         if (pixelSize >=  24) return L"link_24";
         return L"link_16";
     }());
@@ -540,8 +535,8 @@ bool zen::hasLinkExtension(const Zstring& filepath)
     return hasWindowsLinkExtension(filepath);
 
 #elif defined ZEN_LINUX
-    const Zstring& extension = getFileExtension(filepath);
-    return extension == "desktop";
+    const Zstring& ext = getFileExtension(filepath);
+    return ext == "desktop";
 
 #elif defined ZEN_MAC
     return false; //alias files already get their arrow icon via "NSWorkspace::iconForFile"
diff --git a/FreeFileSync/Source/lib/icon_holder.h b/FreeFileSync/Source/lib/icon_holder.h
index 63a93436..9046a18a 100644
--- a/FreeFileSync/Source/lib/icon_holder.h
+++ b/FreeFileSync/Source/lib/icon_holder.h
@@ -18,33 +18,33 @@ struct ImageHolder //prepare conversion to wxImage as much as possible while sta
     ImageHolder() {}
 
     ImageHolder(int w, int h, bool withAlpha) : //init with allocated memory
-        width(w), height(h),
-        rgb(static_cast<unsigned char*>(::malloc(width * height * 3))),
-        alpha(withAlpha ? static_cast<unsigned char*>(::malloc(width * height)) : nullptr) {}
+        width_(w), height_(h),
+        rgb_(static_cast<unsigned char*>(::malloc(w * h * 3))),
+        alpha_(withAlpha ? static_cast<unsigned char*>(::malloc(w * h)) : nullptr) {}
 
     ImageHolder           (ImageHolder&& tmp) = default; //
     ImageHolder& operator=(ImageHolder&& tmp) = default; //move semantics only!
     ImageHolder           (const ImageHolder&) = delete; //
     ImageHolder& operator=(const ImageHolder&) = delete; //
 
-    explicit operator bool() const { return rgb.get() != nullptr; }
+    explicit operator bool() const { return rgb_.get() != nullptr; }
 
-    int getWidth () const { return width;  }
-    int getHeight() const { return height; }
+    int getWidth () const { return width_;  }
+    int getHeight() const { return height_; }
 
-    unsigned char* getRgb  () { return rgb  .get(); }
-    unsigned char* getAlpha() { return alpha.get(); }
+    unsigned char* getRgb  () { return rgb_  .get(); }
+    unsigned char* getAlpha() { return alpha_.get(); }
 
-    unsigned char* releaseRgb  () { return rgb  .release(); }
-    unsigned char* releaseAlpha() { return alpha.release(); }
+    unsigned char* releaseRgb  () { return rgb_  .release(); }
+    unsigned char* releaseAlpha() { return alpha_.release(); }
 
     struct CLibFree { void operator()(unsigned char* p) const { ::free(p); } }; //use malloc/free to allow direct move into wxImage!
 
 private:
-    int width  = 0;
-    int height = 0;
-    std::unique_ptr<unsigned char, CLibFree> rgb;   //optional
-    std::unique_ptr<unsigned char, CLibFree> alpha; //
+    int width_  = 0;
+    int height_ = 0;
+    std::unique_ptr<unsigned char, CLibFree> rgb_;   //optional
+    std::unique_ptr<unsigned char, CLibFree> alpha_; //
 };
 }
 
diff --git a/FreeFileSync/Source/lib/icon_loader.cpp b/FreeFileSync/Source/lib/icon_loader.cpp
index 088fb082..1a1c0610 100644
--- a/FreeFileSync/Source/lib/icon_loader.cpp
+++ b/FreeFileSync/Source/lib/icon_loader.cpp
@@ -90,10 +90,11 @@ ImageHolder copyToImageHolder(const GdkPixbuf* pixbuf)
 IconSizeType getThumbSizeType(int pixelSize)
 {
     //coordinate with IconBuffer::getSize()!
-    if (pixelSize >= 256) return ICON_SIZE_256;
     if (pixelSize >= 128) return ICON_SIZE_128;
     if (pixelSize >=  48) return ICON_SIZE_48;
+#ifdef ZEN_WIN_PRE_VISTA
     if (pixelSize >=  32) return ICON_SIZE_32;
+#endif
     return ICON_SIZE_16;
 }
 
diff --git a/FreeFileSync/Source/lib/localization.cpp b/FreeFileSync/Source/lib/localization.cpp
index 2e715c59..e691e5c9 100644
--- a/FreeFileSync/Source/lib/localization.cpp
+++ b/FreeFileSync/Source/lib/localization.cpp
@@ -158,10 +158,12 @@ std::vector<TranslationInfo> loadTranslations()
 {
     std::vector<TranslationInfo> locMapping;
     {
+        const wchar_t ltrMark = L'\u200E'; //UTF-8: E2 80 8E
+
         //default entry:
         TranslationInfo newEntry;
         newEntry.languageID     = wxLANGUAGE_ENGLISH_US;
-        newEntry.languageName   = L"English (US)";
+        newEntry.languageName   = std::wstring(L"English (US)") + ltrMark; //handle weak ")" for bidi-algorithm
         newEntry.translatorName = L"Zenju";
         newEntry.languageFlag   = L"flag_usa.png";
         newEntry.langFilePath   = Zstr("");
@@ -171,7 +173,7 @@ std::vector<TranslationInfo> loadTranslations()
     //search language files available
     std::vector<Zstring> lngFilePaths;
 
-    traverseFolder(zen::getResourceDir() + Zstr("Languages"), [&](const zen::FileInfo& fi) //FileInfo is ambiguous on OS X
+    traverseFolder(zen::getResourceDirPf() + Zstr("Languages"), [&](const zen::FileInfo& fi) //FileInfo is ambiguous on OS X
     {
         if (pathEndsWith(fi.fullPath, Zstr(".lng")))
             lngFilePaths.push_back(fi.fullPath);
@@ -191,7 +193,7 @@ std::vector<TranslationInfo> loadTranslations()
             assert(!lngHeader.localeName    .empty());
             assert(!lngHeader.flagFile      .empty());
             /*
-            Some ISO codes are used by multiple wxLanguage ids which can lead to incorrect mapping!!!
+            Some ISO codes are used by multiple wxLanguage IDs which can lead to incorrect mapping!!!
             => Identify by description, e.g. "Chinese (Traditional)". The following ids are affected:
                 wxLANGUAGE_CHINESE_TRADITIONAL
                 wxLANGUAGE_ENGLISH_UK
diff --git a/FreeFileSync/Source/lib/parallel_scan.cpp b/FreeFileSync/Source/lib/parallel_scan.cpp
index 1057c530..0c34b534 100644
--- a/FreeFileSync/Source/lib/parallel_scan.cpp
+++ b/FreeFileSync/Source/lib/parallel_scan.cpp
@@ -5,11 +5,13 @@
 // *****************************************************************************
 
 #include "parallel_scan.h"
+#include <chrono>
 #include <zen/file_error.h>
+#include <zen/basic_math.h>
 #include <zen/thread.h>
 #include <zen/scope_guard.h>
 #include <zen/fixed_list.h>
-#include <zen/tick_count.h>
+//#include <zen/tick_count.h>
 #include "db_file.h"
 #include "lock_holder.h"
 
@@ -157,52 +159,53 @@ using BasicWString = Zbase<wchar_t>; //thread-safe string class for UI texts
 class AsyncCallback //actor pattern
 {
 public:
-    AsyncCallback(size_t reportingIntervalMs) : reportingIntervalTicks(reportingIntervalMs * ticksPerSec() / 1000) {}
+    AsyncCallback(size_t reportingIntervalMs) : reportingIntervalMs_(reportingIntervalMs) {}
 
     //blocking call: context of worker thread
     FillBufferCallback::HandleError reportError(const std::wstring& msg, size_t retryNumber) //throw ThreadInterruption
     {
-        std::unique_lock<std::mutex> dummy(lockErrorInfo);
-        interruptibleWait(conditionCanReportError, dummy, [this] { return !errorInfo && !errorResponse; }); //throw ThreadInterruption
+        std::unique_lock<std::mutex> dummy(lockErrorInfo_);
+        interruptibleWait(conditionCanReportError_, dummy, [this] { return !errorInfo_ && !errorResponse_; }); //throw ThreadInterruption
 
-        errorInfo = std::make_unique<std::pair<BasicWString, size_t>>(copyStringTo<BasicWString>(msg), retryNumber);
+        errorInfo_ = std::make_unique<std::pair<BasicWString, size_t>>(copyStringTo<BasicWString>(msg), retryNumber);
 
-        interruptibleWait(conditionGotResponse, dummy, [this] { return static_cast<bool>(errorResponse); }); //throw ThreadInterruption
+        interruptibleWait(conditionGotResponse_, dummy, [this] { return static_cast<bool>(errorResponse_); }); //throw ThreadInterruption
 
-        FillBufferCallback::HandleError rv = *errorResponse;
+        FillBufferCallback::HandleError rv = *errorResponse_;
 
-        errorInfo    .reset();
-        errorResponse.reset();
+        errorInfo_    .reset();
+        errorResponse_.reset();
 
         dummy.unlock(); //optimization for condition_variable::notify_all()
-        conditionCanReportError.notify_all(); //instead of notify_one(); workaround bug: https://svn.boost.org/trac/boost/ticket/7796
+        conditionCanReportError_.notify_all(); //instead of notify_one(); workaround bug: https://svn.boost.org/trac/boost/ticket/7796
 
         return rv;
     }
 
     void processErrors(FillBufferCallback& callback) //context of main thread, call repreatedly
     {
-        std::unique_lock<std::mutex> dummy(lockErrorInfo);
-        if (errorInfo.get() && !errorResponse.get())
+        std::unique_lock<std::mutex> dummy(lockErrorInfo_);
+        if (errorInfo_.get() && !errorResponse_.get())
         {
-            FillBufferCallback::HandleError rv = callback.reportError(copyStringTo<std::wstring>(errorInfo->first), errorInfo->second); //throw!
-            errorResponse = std::make_unique<FillBufferCallback::HandleError>(rv);
+            FillBufferCallback::HandleError rv = callback.reportError(copyStringTo<std::wstring>(errorInfo_->first), errorInfo_->second); //throw!
+            errorResponse_ = std::make_unique<FillBufferCallback::HandleError>(rv);
 
             dummy.unlock(); //optimization for condition_variable::notify_all()
-            conditionGotResponse.notify_all(); //instead of notify_one(); workaround bug: https://svn.boost.org/trac/boost/ticket/7796
+            conditionGotResponse_.notify_all(); //instead of notify_one(); workaround bug: https://svn.boost.org/trac/boost/ticket/7796
         }
     }
 
-    void incrementNotifyingThreadId() { ++notifyingThreadID; } //context of main thread
+    void incrementNotifyingThreadId() { ++notifyingThreadID_; } //context of main thread
 
     //perf optimization: comparison phase is 7% faster by avoiding needless std::wstring contstruction for reportCurrentFile()
-    bool mayReportCurrentFile(int threadID, TickVal& lastReportTime) const
+    bool mayReportCurrentFile(int threadID, std::chrono::steady_clock::time_point& lastReportTime) const
     {
-        if (threadID != notifyingThreadID) //only one thread at a time may report status
+        if (threadID != notifyingThreadID_) //only one thread at a time may report status
             return false;
 
-        const TickVal now = getTicks(); //0 on error
-        if (dist(lastReportTime, now) >= reportingIntervalTicks) //perform ui updates not more often than necessary
+        const auto now = std::chrono::steady_clock::now(); //0 on error
+
+        if (numeric::dist(now, lastReportTime) > std::chrono::milliseconds(reportingIntervalMs_)) //perform ui updates not more often than necessary + handle potential chrono wrap-around!
         {
             lastReportTime = now; //keep "lastReportTime" at worker thread level to avoid locking!
             return true;
@@ -212,24 +215,24 @@ public:
 
     void reportCurrentFile(const std::wstring& filepath) //context of worker thread
     {
-        std::lock_guard<std::mutex> dummy(lockCurrentStatus);
-        currentFile = copyStringTo<BasicWString>(filepath);
+        std::lock_guard<std::mutex> dummy(lockCurrentStatus_);
+        currentFile_ = copyStringTo<BasicWString>(filepath);
     }
 
     std::wstring getCurrentStatus() //context of main thread, call repreatedly
     {
         std::wstring filepath;
         {
-            std::lock_guard<std::mutex> dummy(lockCurrentStatus);
-            filepath = copyStringTo<std::wstring>(currentFile);
+            std::lock_guard<std::mutex> dummy(lockCurrentStatus_);
+            filepath = copyStringTo<std::wstring>(currentFile_);
         }
 
         if (filepath.empty())
             return std::wstring();
 
-        std::wstring statusText = copyStringTo<std::wstring>(textScanning);
+        std::wstring statusText = copyStringTo<std::wstring>(textScanning_);
 
-        const long activeCount = activeWorker;
+        const long activeCount = activeWorker_;
         if (activeCount >= 2)
             statusText += L" [" + replaceCpy(_P("1 thread", "%x threads", activeCount), L"%x", numberTo<std::wstring>(activeCount)) + L"]";
 
@@ -238,33 +241,33 @@ public:
         return statusText;
     }
 
-    void incItemsScanned() { ++itemsScanned; } //perf: irrelevant! scanning is almost entirely file I/O bound, not CPU bound! => no prob having multiple threads poking at the same variable!
-    long getItemsScanned() const { return itemsScanned; }
+    void incItemsScanned() { ++itemsScanned_; } //perf: irrelevant! scanning is almost entirely file I/O bound, not CPU bound! => no prob having multiple threads poking at the same variable!
+    long getItemsScanned() const { return itemsScanned_; }
 
-    void incActiveWorker() { ++activeWorker; }
-    void decActiveWorker() { --activeWorker; }
-    long getActiveWorker() const { return activeWorker; }
+    void incActiveWorker() { ++activeWorker_; }
+    void decActiveWorker() { --activeWorker_; }
+    long getActiveWorker() const { return activeWorker_; }
 
 private:
     //---- error handling ----
-    std::mutex lockErrorInfo;
-    std::condition_variable conditionCanReportError;
-    std::condition_variable conditionGotResponse;
-    std::unique_ptr<std::pair<BasicWString, size_t>> errorInfo; //error message + retry number
-    std::unique_ptr<FillBufferCallback::HandleError> errorResponse;
+    std::mutex lockErrorInfo_;
+    std::condition_variable conditionCanReportError_;
+    std::condition_variable conditionGotResponse_;
+    std::unique_ptr<std::pair<BasicWString, size_t>> errorInfo_; //error message + retry number
+    std::unique_ptr<FillBufferCallback::HandleError> errorResponse_;
 
     //---- status updates ----
-    std::atomic<int> notifyingThreadID { 0 }; //CAVEAT: do NOT use boost::thread::id: https://svn.boost.org/trac/boost/ticket/5754
+    std::atomic<int> notifyingThreadID_ { 0 }; //CAVEAT: do NOT use boost::thread::id: https://svn.boost.org/trac/boost/ticket/5754
 
-    std::mutex lockCurrentStatus; //use a different lock for current file: continue traversing while some thread may process an error
-    BasicWString currentFile;
-    const std::int64_t reportingIntervalTicks;
+    std::mutex lockCurrentStatus_; //use a different lock for current file: continue traversing while some thread may process an error
+    BasicWString currentFile_;
+    const std::int64_t reportingIntervalMs_;
 
-    const BasicWString textScanning { copyStringTo<BasicWString>(_("Scanning:")) }; //this one is (currently) not shared and could be made a std::wstring, but we stay consistent and use thread-safe variables in this class only!
+    const BasicWString textScanning_ { copyStringTo<BasicWString>(_("Scanning:")) }; //this one is (currently) not shared and could be made a std::wstring, but we stay consistent and use thread-safe variables in this class only!
 
     //---- status updates II (lock free) ----
-    std::atomic<int> itemsScanned{ 0 }; //std:atomic is uninitialized by default!
-    std::atomic<int> activeWorker{ 0 }; //
+    std::atomic<int> itemsScanned_{ 0 }; //std:atomic is uninitialized by default!
+    std::atomic<int> activeWorker_{ 0 }; //
 };
 
 //-------------------------------------------------------------------------------------------------
@@ -296,7 +299,7 @@ public:
 
     AsyncCallback& acb_;
     const int threadID_;
-    TickVal lastReportTime;
+    std::chrono::steady_clock::time_point lastReportTime_;
 };
 
 
@@ -339,7 +342,7 @@ void DirCallback::onFile(const FileInfo& fi) //throw ThreadInterruption
     const Zstring fileRelPath = parentRelPathPf_ + fi.itemName;
 
     //update status information no matter whether item is excluded or not!
-    if (cfg.acb_.mayReportCurrentFile(cfg.threadID_, cfg.lastReportTime))
+    if (cfg.acb_.mayReportCurrentFile(cfg.threadID_, cfg.lastReportTime_))
         cfg.acb_.reportCurrentFile(AFS::getDisplayPath(AFS::appendRelPath(cfg.baseFolderPath_, fileRelPath)));
 
     //------------------------------------------------------------------------------------
@@ -371,7 +374,7 @@ std::unique_ptr<AFS::TraverserCallback> DirCallback::onDir(const DirInfo& di) //
     const Zstring& folderRelPath = parentRelPathPf_ + di.itemName;
 
     //update status information no matter whether item is excluded or not!
-    if (cfg.acb_.mayReportCurrentFile(cfg.threadID_, cfg.lastReportTime))
+    if (cfg.acb_.mayReportCurrentFile(cfg.threadID_, cfg.lastReportTime_))
         cfg.acb_.reportCurrentFile(AFS::getDisplayPath(AFS::appendRelPath(cfg.baseFolderPath_, folderRelPath)));
 
     //------------------------------------------------------------------------------------
@@ -390,11 +393,11 @@ std::unique_ptr<AFS::TraverserCallback> DirCallback::onDir(const DirInfo& di) //
     if (level_ > 100) //Win32 traverser: stack overflow approximately at level 1000
         if (!tryReportingItemError([&] //check after FolderContainer::addSubFolder()
     {
-        throw FileError(replaceCpy(_("Cannot enumerate directory %x."), L"%x", AFS::getDisplayPath(AFS::appendRelPath(cfg.baseFolderPath_, folderRelPath))), L"Endless recursion.");
+        throw FileError(replaceCpy(_("Cannot read directory %x."), L"%x", AFS::getDisplayPath(AFS::appendRelPath(cfg.baseFolderPath_, folderRelPath))), L"Endless recursion.");
         }, *this, di.itemName))
     return nullptr;
 
-    return std::make_unique<DirCallback>(cfg, folderRelPath + FILE_NAME_SEPARATOR, subFolder, level_ + 1); //releaseDirTraverser() is guaranteed to be called in any case
+    return std::make_unique<DirCallback>(cfg, folderRelPath + FILE_NAME_SEPARATOR, subFolder, level_ + 1);
 }
 
 
@@ -405,7 +408,7 @@ DirCallback::HandleLink DirCallback::onSymlink(const SymlinkInfo& si) //throw Th
     const Zstring& linkRelPath = parentRelPathPf_ + si.itemName;
 
     //update status information no matter whether item is excluded or not!
-    if (cfg.acb_.mayReportCurrentFile(cfg.threadID_, cfg.lastReportTime))
+    if (cfg.acb_.mayReportCurrentFile(cfg.threadID_, cfg.lastReportTime_))
         cfg.acb_.reportCurrentFile(AFS::getDisplayPath(AFS::appendRelPath(cfg.baseFolderPath_, linkRelPath)));
 
     switch (cfg.handleSymlinks_)
@@ -500,7 +503,7 @@ public:
         acb_->incActiveWorker();
         ZEN_ON_SCOPE_EXIT(acb_->decActiveWorker());
 
-        if (acb_->mayReportCurrentFile(travCfg.threadID_, travCfg.lastReportTime))
+        if (acb_->mayReportCurrentFile(travCfg.threadID_, travCfg.lastReportTime_))
             acb_->reportCurrentFile(AFS::getDisplayPath(travCfg.baseFolderPath_)); //just in case first directory access is blocking
 
         DirCallback cb(travCfg, Zstring(), outputContainer, 0);
diff --git a/FreeFileSync/Source/lib/process_xml.cpp b/FreeFileSync/Source/lib/process_xml.cpp
index ba681397..1e31cabf 100644
--- a/FreeFileSync/Source/lib/process_xml.cpp
+++ b/FreeFileSync/Source/lib/process_xml.cpp
@@ -96,7 +96,7 @@ XmlGlobalSettings::XmlGlobalSettings()
 
 Zstring xmlAccess::getGlobalConfigFile()
 {
-    return zen::getConfigDir() + Zstr("GlobalSettings.xml");
+    return zen::getConfigDirPathPf() + Zstr("GlobalSettings.xml");
 }
 
 
@@ -492,15 +492,15 @@ void writeText(const ColumnTypeNavi& value, std::string& output)
 {
     switch (value)
     {
-        case ColumnTypeNavi::BYTES:
-            output = "Bytes";
-            break;
-        case ColumnTypeNavi::DIRECTORY:
+        case ColumnTypeNavi::FOLDER_NAME:
             output = "Tree";
             break;
         case ColumnTypeNavi::ITEM_COUNT:
             output = "Count";
             break;
+        case ColumnTypeNavi::BYTES:
+            output = "Bytes";
+            break;
     }
 }
 
@@ -508,12 +508,12 @@ template <> inline
 bool readText(const std::string& input, ColumnTypeNavi& value)
 {
     const std::string tmp = trimCpy(input);
-    if (tmp == "Bytes")
-        value = ColumnTypeNavi::BYTES;
-    else if (tmp == "Tree")
-        value = ColumnTypeNavi::DIRECTORY;
+    if (tmp == "Tree")
+        value = ColumnTypeNavi::FOLDER_NAME;
     else if (tmp == "Count")
         value = ColumnTypeNavi::ITEM_COUNT;
+    else if (tmp == "Bytes")
+        value = ColumnTypeNavi::BYTES;
     else
         return false;
     return true;
@@ -1204,7 +1204,6 @@ void readConfig(const XmlIn& in, XmlGlobalSettings& config, int formatVer)
     //last update check
     inGui["LastOnlineCheck"  ](config.gui.lastUpdateCheck);
     inGui["LastOnlineVersion"](config.gui.lastOnlineVersion);
-    inGui["LastOnlineChanges"](config.gui.lastOnlineChangeLog);
 
     //batch specific global settings
     //XmlIn inBatch = in["Batch"];
@@ -1599,7 +1598,6 @@ void writeConfig(const XmlGlobalSettings& config, XmlOut& out)
     //last update check
     outGui["LastOnlineCheck"  ](config.gui.lastUpdateCheck);
     outGui["LastOnlineVersion"](config.gui.lastOnlineVersion);
-    outGui["LastOnlineChanges"](config.gui.lastOnlineChangeLog);
 
     //batch specific global settings
     //XmlOut outBatch = out["Batch"];
diff --git a/FreeFileSync/Source/lib/process_xml.h b/FreeFileSync/Source/lib/process_xml.h
index f29ed729..16659cc5 100644
--- a/FreeFileSync/Source/lib/process_xml.h
+++ b/FreeFileSync/Source/lib/process_xml.h
@@ -251,8 +251,7 @@ struct XmlGlobalSettings
         };
 
         time_t lastUpdateCheck = 0; //number of seconds since 00:00 hours, Jan 1, 1970 UTC
-        std::wstring lastOnlineVersion;
-        std::wstring lastOnlineChangeLog;
+        std::string lastOnlineVersion;
     } gui;
 };
 
diff --git a/FreeFileSync/Source/lib/resolve_path.cpp b/FreeFileSync/Source/lib/resolve_path.cpp
index b081e1e9..a67460bd 100644
--- a/FreeFileSync/Source/lib/resolve_path.cpp
+++ b/FreeFileSync/Source/lib/resolve_path.cpp
@@ -722,7 +722,7 @@ void NetworkConnector::connect(const Credentials& cred) //throw FileError
     assert(!cred.remoteName.empty());
     trgRes.lpRemoteName = const_cast<LPWSTR>(cred.remoteName.c_str()); //
     if (!cred.localName.empty())
-        trgRes.lpLocalName  = const_cast<LPWSTR>(cred.localName.c_str());  //lpNetResource is marked "__in", seems WNetAddConnection2 is not const correct!
+        trgRes.lpLocalName = const_cast<LPWSTR>(cred.localName.c_str());  //lpNetResource is marked "__in", seems WNetAddConnection2 is not const correct!
 
     const DWORD rv = ::WNetAddConnection2(&trgRes, //__in  LPNETRESOURCE lpNetResource,
                                           nullptr, //__in  LPCTSTR lpPassword,
@@ -736,6 +736,7 @@ void NetworkConnector::connect(const Credentials& cred) //throw FileError
     //1219 ERROR_SESSION_CREDENTIAL_CONFLICT   Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed. Disconnect all previous connections to the server or shared resource and try again.
     //1326 ERROR_LOGON_FAILURE Logon failure: unknown user name or bad password.
     //1236 ERROR_CONNECTION_ABORTED
+    //1244 ERROR_NOT_AUTHENTICATED
 }
 }
 
diff --git a/FreeFileSync/Source/lib/status_handler.cpp b/FreeFileSync/Source/lib/status_handler.cpp
index 1d940cc9..55765fc3 100644
--- a/FreeFileSync/Source/lib/status_handler.cpp
+++ b/FreeFileSync/Source/lib/status_handler.cpp
@@ -5,21 +5,22 @@
 // *****************************************************************************
 
 #include "status_handler.h"
-#include <zen/tick_count.h>
+#include <chrono>
+#include <zen/basic_math.h>
 
 using namespace zen;
 
 
 namespace
 {
-const std::int64_t TICKS_UPDATE_INTERVAL = UI_UPDATE_INTERVAL* ticksPerSec() / 1000;
-TickVal lastExec = getTicks();
+std::chrono::steady_clock::time_point lastExec;
 };
 
 bool zen::updateUiIsAllowed()
 {
-    const TickVal now = getTicks(); //0 on error
-    if (dist(lastExec, now) >= TICKS_UPDATE_INTERVAL) //perform ui updates not more often than necessary
+    const auto now = std::chrono::steady_clock::now();
+
+    if (numeric::dist(now, lastExec) > std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS)) //handle potential chrono wrap-around!
     {
         lastExec = now;
         return true;
diff --git a/FreeFileSync/Source/process_callback.h b/FreeFileSync/Source/process_callback.h
index e7291196..51dd956f 100644
--- a/FreeFileSync/Source/process_callback.h
+++ b/FreeFileSync/Source/process_callback.h
@@ -12,7 +12,7 @@
 
 
 //interface for comparison and synchronization process status updates (used by GUI or Batch mode)
-const int UI_UPDATE_INTERVAL = 100; //unit: [ms]; perform ui updates not more often than necessary,
+const int UI_UPDATE_INTERVAL_MS = 100; //unit: [ms]; perform ui updates not more often than necessary,
 //100 seems to be a good value with only a minimal performance loss; also used by Win 7 copy progress bar
 //this one is required by async directory existence check!
 
diff --git a/FreeFileSync/Source/synchronization.cpp b/FreeFileSync/Source/synchronization.cpp
index 3b58d4ba..4f36ded1 100644
--- a/FreeFileSync/Source/synchronization.cpp
+++ b/FreeFileSync/Source/synchronization.cpp
@@ -91,14 +91,17 @@ void SyncStatistics::processFile(const FilePair& file)
 
         case SO_DELETE_LEFT:
             ++deleteLeft_;
+            physicalDeleteLeft_ = true;
             break;
 
         case SO_DELETE_RIGHT:
             ++deleteRight_;
+            physicalDeleteRight_ = true;
             break;
 
         case SO_MOVE_LEFT_TARGET:
             ++updateLeft_;
+            //physicalDeleteLeft_ ? -> usually, no; except when falling back to "copy + delete"
             break;
 
         case SO_MOVE_RIGHT_TARGET:
@@ -112,15 +115,17 @@ void SyncStatistics::processFile(const FilePair& file)
         case SO_OVERWRITE_LEFT:
             ++updateLeft_;
             bytesToProcess_ += static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
+            physicalDeleteLeft_ = true;
             break;
 
         case SO_OVERWRITE_RIGHT:
             ++updateRight_;
             bytesToProcess_ += static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
+            physicalDeleteRight_ = true;
             break;
 
         case SO_UNRESOLVED_CONFLICT:
-            conflictMsgs_.emplace_back(file.getPairRelativePath(), file.getSyncOpConflict());
+            conflictMsgs_.push_back({ file.getPairRelativePath(), file.getSyncOpConflict() });
             break;
 
         case SO_COPY_METADATA_TO_LEFT:
@@ -153,24 +158,28 @@ void SyncStatistics::processLink(const SymlinkPair& link)
 
         case SO_DELETE_LEFT:
             ++deleteLeft_;
+            physicalDeleteLeft_ = true;
             break;
 
         case SO_DELETE_RIGHT:
             ++deleteRight_;
+            physicalDeleteRight_ = true;
             break;
 
         case SO_OVERWRITE_LEFT:
         case SO_COPY_METADATA_TO_LEFT:
             ++updateLeft_;
+            physicalDeleteLeft_ = true;
             break;
 
         case SO_OVERWRITE_RIGHT:
         case SO_COPY_METADATA_TO_RIGHT:
             ++updateRight_;
+            physicalDeleteRight_ = true;
             break;
 
         case SO_UNRESOLVED_CONFLICT:
-            conflictMsgs_.emplace_back(link.getPairRelativePath(), link.getSyncOpConflict());
+            conflictMsgs_.push_back({ link.getPairRelativePath(), link.getSyncOpConflict() });
             break;
 
         case SO_MOVE_LEFT_SOURCE:
@@ -198,16 +207,18 @@ void SyncStatistics::processFolder(const FolderPair& folder)
             ++createRight_;
             break;
 
-        case SO_DELETE_LEFT: //if deletion variant == user-defined directory existing on other volume, this results in a full copy + delete operation!
+        case SO_DELETE_LEFT: //if deletion variant == versioning with user-defined directory existing on other volume, this results in a full copy + delete operation!
             ++deleteLeft_;    //however we cannot (reliably) anticipate this situation, fortunately statistics can be adapted during sync!
+            physicalDeleteLeft_ = true;
             break;
 
         case SO_DELETE_RIGHT:
             ++deleteRight_;
+            physicalDeleteRight_ = true;
             break;
 
         case SO_UNRESOLVED_CONFLICT:
-            conflictMsgs_.emplace_back(folder.getPairRelativePath(), folder.getSyncOpConflict());
+            conflictMsgs_.push_back({ folder.getPairRelativePath(), folder.getSyncOpConflict() });
             break;
 
         case SO_OVERWRITE_LEFT:
@@ -262,6 +273,36 @@ std::vector<zen::FolderPairSyncCfg> zen::extractSyncCfg(const MainConfiguration&
 
 namespace
 {
+inline
+Opt<SelectedSide> getTargetDirection(SyncOperation syncOp)
+{
+    switch (syncOp)
+    {
+        case SO_CREATE_NEW_LEFT:
+        case SO_DELETE_LEFT:
+        case SO_OVERWRITE_LEFT:
+        case SO_COPY_METADATA_TO_LEFT:
+        case SO_MOVE_LEFT_SOURCE:
+        case SO_MOVE_LEFT_TARGET:
+            return LEFT_SIDE;
+
+        case SO_CREATE_NEW_RIGHT:
+        case SO_DELETE_RIGHT:
+        case SO_OVERWRITE_RIGHT:
+        case SO_COPY_METADATA_TO_RIGHT:
+        case SO_MOVE_RIGHT_SOURCE:
+        case SO_MOVE_RIGHT_TARGET:
+            return RIGHT_SIDE;
+
+        case SO_DO_NOTHING:
+        case SO_EQUAL:
+        case SO_UNRESOLVED_CONFLICT:
+            break; //nothing to do
+    }
+    return NoValue();
+}
+
+
 //test if user accidentally selected the wrong folders to sync
 bool significantDifferenceDetected(const SyncStatistics& folderPairStat)
 {
@@ -542,12 +583,10 @@ public:
     {
         MinimumDiskSpaceNeeded inst;
         inst.recurse(baseFolder);
-        return std::make_pair(inst.spaceNeededLeft, inst.spaceNeededRight);
+        return std::make_pair(inst.spaceNeededLeft_, inst.spaceNeededRight_);
     }
 
 private:
-    MinimumDiskSpaceNeeded() {}
-
     void recurse(const HierarchyObject& hierObj)
     {
         //don't process directories
@@ -557,33 +596,33 @@ private:
             switch (file.getSyncOperation()) //evaluate comparison result and sync direction
             {
                 case SO_CREATE_NEW_LEFT:
-                    spaceNeededLeft += static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
+                    spaceNeededLeft_ += static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
                     break;
 
                 case SO_CREATE_NEW_RIGHT:
-                    spaceNeededRight += static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
+                    spaceNeededRight_ += static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
                     break;
 
                 case SO_DELETE_LEFT:
                     //if (freeSpaceDelLeft_)
-                    spaceNeededLeft -= static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
+                    spaceNeededLeft_ -= static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
                     break;
 
                 case SO_DELETE_RIGHT:
                     //if (freeSpaceDelRight_)
-                    spaceNeededRight -= static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
+                    spaceNeededRight_ -= static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
                     break;
 
                 case SO_OVERWRITE_LEFT:
                     //if (freeSpaceDelLeft_)
-                    spaceNeededLeft -= static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
-                    spaceNeededLeft += static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
+                    spaceNeededLeft_ -= static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
+                    spaceNeededLeft_ += static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
                     break;
 
                 case SO_OVERWRITE_RIGHT:
                     //if (freeSpaceDelRight_)
-                    spaceNeededRight -= static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
-                    spaceNeededRight += static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
+                    spaceNeededRight_ -= static_cast<std::int64_t>(file.getFileSize<RIGHT_SIDE>());
+                    spaceNeededRight_ += static_cast<std::int64_t>(file.getFileSize<LEFT_SIDE>());
                     break;
 
                 case SO_DO_NOTHING:
@@ -606,8 +645,8 @@ private:
             recurse(folder);
     }
 
-    std::int64_t spaceNeededLeft  = 0;
-    std::int64_t spaceNeededRight = 0;
+    std::int64_t spaceNeededLeft_  = 0;
+    std::int64_t spaceNeededRight_ = 0;
 };
 
 //----------------------------------------------------------------------------------------
@@ -642,16 +681,16 @@ public:
     }
 
 private:
-    enum PassId
+    enum PassNo
     {
         PASS_ONE, //delete files
         PASS_TWO, //create, modify
-        PASS_NEVER //skip
+        PASS_NEVER //skip item
     };
 
-    static PassId getPass(const FilePair&    file);
-    static PassId getPass(const SymlinkPair& link);
-    static PassId getPass(const FolderPair&  folder);
+    static PassNo getPass(const FilePair&    file);
+    static PassNo getPass(const SymlinkPair& link);
+    static PassNo getPass(const FolderPair&  folder);
 
     template <SelectedSide side>
     void prepare2StepMove(FilePair& sourceObj, FilePair& targetObj); //throw FileError
@@ -660,7 +699,7 @@ private:
     void manageFileMove(FilePair& sourceObj, FilePair& targetObj); //throw FileError
 
     void runZeroPass(HierarchyObject& hierObj);
-    template <PassId pass>
+    template <PassNo pass>
     void runPass(HierarchyObject& hierObj); //throw X
 
     void synchronizeFile(FilePair& file);
@@ -964,7 +1003,7 @@ void SynchronizeFolderPair::runZeroPass(HierarchyObject& hierObj)
 // - support change in type: overwrite file by directory, symlink by file, ect.
 
 inline
-SynchronizeFolderPair::PassId SynchronizeFolderPair::getPass(const FilePair& file)
+SynchronizeFolderPair::PassNo SynchronizeFolderPair::getPass(const FilePair& file)
 {
     switch (file.getSyncOperation()) //evaluate comparison result and sync direction
     {
@@ -1002,7 +1041,7 @@ SynchronizeFolderPair::PassId SynchronizeFolderPair::getPass(const FilePair& fil
 
 
 inline
-SynchronizeFolderPair::PassId SynchronizeFolderPair::getPass(const SymlinkPair& link)
+SynchronizeFolderPair::PassNo SynchronizeFolderPair::getPass(const SymlinkPair& link)
 {
     switch (link.getSyncOperation()) //evaluate comparison result and sync direction
     {
@@ -1034,7 +1073,7 @@ SynchronizeFolderPair::PassId SynchronizeFolderPair::getPass(const SymlinkPair&
 
 
 inline
-SynchronizeFolderPair::PassId SynchronizeFolderPair::getPass(const FolderPair& folder)
+SynchronizeFolderPair::PassNo SynchronizeFolderPair::getPass(const FolderPair& folder)
 {
     switch (folder.getSyncOperation()) //evaluate comparison result and sync direction
     {
@@ -1065,7 +1104,7 @@ SynchronizeFolderPair::PassId SynchronizeFolderPair::getPass(const FolderPair& f
 }
 
 
-template <SynchronizeFolderPair::PassId pass>
+template <SynchronizeFolderPair::PassNo pass>
 void SynchronizeFolderPair::runPass(HierarchyObject& hierObj) //throw X
 {
     //synchronize files:
@@ -1091,36 +1130,6 @@ void SynchronizeFolderPair::runPass(HierarchyObject& hierObj) //throw X
 //---------------------------------------------------------------------------------------------------------------
 
 inline
-Opt<SelectedSide> getTargetDirection(SyncOperation syncOp)
-{
-    switch (syncOp)
-    {
-        case SO_CREATE_NEW_LEFT:
-        case SO_DELETE_LEFT:
-        case SO_OVERWRITE_LEFT:
-        case SO_COPY_METADATA_TO_LEFT:
-        case SO_MOVE_LEFT_SOURCE:
-        case SO_MOVE_LEFT_TARGET:
-            return LEFT_SIDE;
-
-        case SO_CREATE_NEW_RIGHT:
-        case SO_DELETE_RIGHT:
-        case SO_OVERWRITE_RIGHT:
-        case SO_COPY_METADATA_TO_RIGHT:
-        case SO_MOVE_RIGHT_SOURCE:
-        case SO_MOVE_RIGHT_TARGET:
-            return RIGHT_SIDE;
-
-        case SO_DO_NOTHING:
-        case SO_EQUAL:
-        case SO_UNRESOLVED_CONFLICT:
-            break; //nothing to do
-    }
-    return NoValue();
-}
-
-
-inline
 void SynchronizeFolderPair::synchronizeFile(FilePair& file)
 {
     const SyncOperation syncOp = file.getSyncOperation();
@@ -1855,13 +1864,14 @@ void zen::synchronize(const TimeComp& timeStamp,
     {
         int     itemsTotal = 0;
         int64_t bytesTotal = 0;
-        for (auto j = begin(folderCmp); j != end(folderCmp); ++j)
+        std::for_each(begin(folderCmp), end(folderCmp),
+                      [&](const BaseFolderPair& baseFolder)
         {
-            SyncStatistics fpStats(*j);
+            SyncStatistics fpStats(baseFolder);
             itemsTotal += getCUD(fpStats);
             bytesTotal += fpStats.getBytesToProcess();
             folderPairStats.push_back(fpStats);
-        }
+        });
 
         //inform about the total amount of data that will be processed from now on
         //keep at beginning so that all gui elements are initialized properly
@@ -1903,15 +1913,16 @@ void zen::synchronize(const TimeComp& timeStamp,
 
     //aggregate information
     std::map<AbstractPath, ReadWriteCount, AFS::LessAbstractPath> dirReadWriteCount; //count read/write accesses
-    for (auto j = begin(folderCmp); j != end(folderCmp); ++j)
+    std::for_each(begin(folderCmp), end(folderCmp),
+                  [&](const BaseFolderPair& baseFolder)
     {
         //create all entries first! otherwise counting accesses would be too complex during later inserts!
 
-        if (!AFS::isNullPath(j->getAbstractPath<LEFT_SIDE>())) //empty folder is always dependent => exclude!
-            dirReadWriteCount[j->getAbstractPath<LEFT_SIDE>()];
-        if (!AFS::isNullPath(j->getAbstractPath<RIGHT_SIDE>()))
-            dirReadWriteCount[j->getAbstractPath<RIGHT_SIDE>()];
-    }
+        if (!AFS::isNullPath(baseFolder.getAbstractPath<LEFT_SIDE>())) //empty folder is always dependent => exclude!
+            dirReadWriteCount[baseFolder.getAbstractPath<LEFT_SIDE>()];
+        if (!AFS::isNullPath(baseFolder.getAbstractPath<RIGHT_SIDE>()))
+            dirReadWriteCount[baseFolder.getAbstractPath<RIGHT_SIDE>()];
+    });
 
     auto incReadCount = [&](const AbstractPath& baseFolderPath)
     {
@@ -1936,9 +1947,10 @@ void zen::synchronize(const TimeComp& timeStamp,
     std::map<AbstractPath, bool, AFS::LessAbstractPath> recyclerSupported; //expensive to determine on Win XP => buffer + check recycle bin existence only once per base folder!
 
     //start checking folder pairs
-    for (auto j = begin(folderCmp); j != end(folderCmp); ++j)
+    for (auto itBase = begin(folderCmp); itBase != end(folderCmp); ++itBase)
     {
-        const size_t folderIndex = j - begin(folderCmp);
+        BaseFolderPair& baseFolder = *itBase;
+        const size_t folderIndex = itBase - begin(folderCmp);
         const FolderPairSyncCfg& folderPairCfg  = syncConfig     [folderIndex];
         const SyncStatistics&    folderPairStat = folderPairStats[folderIndex];
 
@@ -1946,13 +1958,21 @@ void zen::synchronize(const TimeComp& timeStamp,
         append(unresolvedConflicts, folderPairStat.getConflicts());
 
         //exclude a few pathological cases (including empty left, right folders)
-        if (AFS::equalAbstractPath(j->getAbstractPath< LEFT_SIDE>(),
-                                   j->getAbstractPath<RIGHT_SIDE>()))
+        if (AFS::equalAbstractPath(baseFolder.getAbstractPath< LEFT_SIDE>(),
+                                   baseFolder.getAbstractPath<RIGHT_SIDE>()))
         {
             jobType[folderIndex] = FolderPairJobType::SKIP;
             continue;
         }
 
+        //skip folder pair if there is nothing to do (except for two-way mode and move-detection, where DB files need to be updated)
+        //-> skip creating (not yet existing) base directories in particular if there's no need
+        if (getCUD(folderPairStat) == 0)
+        {
+            jobType[folderIndex] = FolderPairJobType::ALREADY_IN_SYNC;
+            continue;
+        }
+
         const bool writeLeft = folderPairStat.createCount<LEFT_SIDE>() +
                                folderPairStat.updateCount<LEFT_SIDE>() +
                                folderPairStat.deleteCount<LEFT_SIDE>() > 0;
@@ -1961,36 +1981,29 @@ void zen::synchronize(const TimeComp& timeStamp,
                                 folderPairStat.updateCount<RIGHT_SIDE>() +
                                 folderPairStat.deleteCount<RIGHT_SIDE>() > 0;
 
-        //skip folder pair if there is nothing to do (except for two-way mode and move-detection, where DB files need to be updated)
-        //-> skip creating (not yet existing) base directories in particular if there's no need
-        if (!writeLeft && !writeRight)
-        {
-            jobType[folderIndex] = FolderPairJobType::ALREADY_IN_SYNC;
-            continue;
-        }
-
         //aggregate information of folders used by multiple pairs in read/write access
-        if (!AFS::havePathDependency(j->getAbstractPath<LEFT_SIDE>(), j->getAbstractPath<RIGHT_SIDE>()))
+        if (!AFS::havePathDependency(baseFolder.getAbstractPath<LEFT_SIDE >(),
+                                     baseFolder.getAbstractPath<RIGHT_SIDE>()))
         {
             if (writeLeft)
-                incWriteCount(j->getAbstractPath<LEFT_SIDE>());
+                incWriteCount(baseFolder.getAbstractPath<LEFT_SIDE>());
             else if (writeRight)
-                incReadCount (j->getAbstractPath<LEFT_SIDE>());
+                incReadCount (baseFolder.getAbstractPath<LEFT_SIDE>());
 
             if (writeRight)
-                incWriteCount(j->getAbstractPath<RIGHT_SIDE>());
+                incWriteCount(baseFolder.getAbstractPath<RIGHT_SIDE>());
             else if (writeLeft)
-                incReadCount (j->getAbstractPath<RIGHT_SIDE>());
+                incReadCount (baseFolder.getAbstractPath<RIGHT_SIDE>());
         }
         else //if folder pair contains two dependent folders, a warning was already issued after comparison; in this context treat as one write access at most
         {
             if (writeLeft || writeRight)
-                incWriteCount(j->getAbstractPath<LEFT_SIDE>());
+                incWriteCount(baseFolder.getAbstractPath<LEFT_SIDE>());
         }
 
         //check for empty target folder paths: this only makes sense if empty field is source (and no DB files need to be created)
-        if ((AFS::isNullPath(j->getAbstractPath< LEFT_SIDE>()) && (writeLeft  || folderPairCfg.saveSyncDB_)) ||
-            (AFS::isNullPath(j->getAbstractPath<RIGHT_SIDE>()) && (writeRight || folderPairCfg.saveSyncDB_)))
+        if ((AFS::isNullPath(baseFolder.getAbstractPath< LEFT_SIDE>()) && (writeLeft  || folderPairCfg.saveSyncDB_)) ||
+            (AFS::isNullPath(baseFolder.getAbstractPath<RIGHT_SIDE>()) && (writeRight || folderPairCfg.saveSyncDB_)))
         {
             callback.reportFatalError(_("Target folder input field must not be empty."));
             jobType[folderIndex] = FolderPairJobType::SKIP;
@@ -2000,38 +2013,37 @@ void zen::synchronize(const TimeComp& timeStamp,
         //check for network drops after comparison
         // - convenience: exit sync right here instead of showing tons of errors during file copy
         // - early failure! there's no point in evaluating subsequent warnings
-        if (baseFolderDrop< LEFT_SIDE>(*j, folderAccessTimeout, callback) ||
-            baseFolderDrop<RIGHT_SIDE>(*j, folderAccessTimeout, callback))
+        if (baseFolderDrop< LEFT_SIDE>(baseFolder, folderAccessTimeout, callback) ||
+            baseFolderDrop<RIGHT_SIDE>(baseFolder, folderAccessTimeout, callback))
         {
             jobType[folderIndex] = FolderPairJobType::SKIP;
             continue;
         }
 
         //allow propagation of deletions only from *null-* or *existing* source folder:
-        auto sourceFolderMissing = [&](const AbstractPath& baseFolder, bool wasExisting) //we need to evaluate existence status from time of comparison!
+        auto sourceFolderMissing = [&](const AbstractPath& baseFolderPath, bool wasExisting) //we need to evaluate existence status from time of comparison!
         {
-            if (!AFS::isNullPath(baseFolder))
+            if (!AFS::isNullPath(baseFolderPath))
                 //PERMANENT network drop: avoid data loss when source directory is not found AND user chose to ignore errors (else we wouldn't arrive here)
                 if (folderPairStat.deleteCount() > 0) //check deletions only... (respect filtered items!)
                     //folderPairStat.conflictCount() == 0 && -> there COULD be conflicts for <Two way> variant if directory existence check fails, but loading sync.ffs_db succeeds
                     //https://sourceforge.net/tracker/?func=detail&atid=1093080&aid=3531351&group_id=234430 -> fixed, but still better not consider conflicts!
                     if (!wasExisting) //avoid race-condition: we need to evaluate existence status from time of comparison!
                     {
-                        callback.reportFatalError(replaceCpy(_("Source folder %x not found."), L"%x", fmtPath(AFS::getDisplayPath(baseFolder))));
+                        callback.reportFatalError(replaceCpy(_("Source folder %x not found."), L"%x", fmtPath(AFS::getDisplayPath(baseFolderPath))));
                         return true;
                     }
             return false;
         };
-        if (sourceFolderMissing(j->getAbstractPath< LEFT_SIDE>(), j->isExisting< LEFT_SIDE>()) ||
-            sourceFolderMissing(j->getAbstractPath<RIGHT_SIDE>(), j->isExisting<RIGHT_SIDE>()))
+        if (sourceFolderMissing(baseFolder.getAbstractPath< LEFT_SIDE>(), baseFolder.isExisting< LEFT_SIDE>()) ||
+            sourceFolderMissing(baseFolder.getAbstractPath<RIGHT_SIDE>(), baseFolder.isExisting<RIGHT_SIDE>()))
         {
             jobType[folderIndex] = FolderPairJobType::SKIP;
             continue;
         }
 
         //check if user-defined directory for deletion was specified
-        if (folderPairCfg.handleDeletion == DeletionPolicy::VERSIONING &&
-            folderPairStat.updateCount() + folderPairStat.deleteCount() > 0)
+        if (folderPairCfg.handleDeletion == DeletionPolicy::VERSIONING)
         {
             if (trimCpy(folderPairCfg.versioningFolderPhrase).empty())
             {
@@ -2043,11 +2055,11 @@ void zen::synchronize(const TimeComp& timeStamp,
         }
 
         //check if more than 50% of total number of files/dirs are to be created/overwritten/deleted
-        if (!AFS::isNullPath(j->getAbstractPath< LEFT_SIDE>()) &&
-            !AFS::isNullPath(j->getAbstractPath<RIGHT_SIDE>()))
+        if (!AFS::isNullPath(baseFolder.getAbstractPath< LEFT_SIDE>()) &&
+            !AFS::isNullPath(baseFolder.getAbstractPath<RIGHT_SIDE>()))
             if (significantDifferenceDetected(folderPairStat))
-                significantDiffPairs.emplace_back(j->getAbstractPath< LEFT_SIDE>(),
-                                                  j->getAbstractPath<RIGHT_SIDE>());
+                significantDiffPairs.emplace_back(baseFolder.getAbstractPath< LEFT_SIDE>(),
+                                                  baseFolder.getAbstractPath<RIGHT_SIDE>());
 
         //check for sufficient free diskspace
         auto checkSpace = [&](const AbstractPath& baseFolderPath, std::int64_t minSpaceNeeded)
@@ -2063,9 +2075,9 @@ void zen::synchronize(const TimeComp& timeStamp,
                 }
                 catch (FileError&) {} //for warning only => no need for tryReportingError()
         };
-        const std::pair<std::int64_t, std::int64_t> spaceNeeded = MinimumDiskSpaceNeeded::calculate(*j);
-        checkSpace(j->getAbstractPath< LEFT_SIDE>(), spaceNeeded.first);
-        checkSpace(j->getAbstractPath<RIGHT_SIDE>(), spaceNeeded.second);
+        const std::pair<std::int64_t, std::int64_t> spaceNeeded = MinimumDiskSpaceNeeded::calculate(baseFolder);
+        checkSpace(baseFolder.getAbstractPath< LEFT_SIDE>(), spaceNeeded.first);
+        checkSpace(baseFolder.getAbstractPath<RIGHT_SIDE>(), spaceNeeded.second);
 
         //windows: check if recycle bin really exists; if not, Windows will silently delete, which is wrong
         auto checkRecycler = [&](const AbstractPath& baseFolderPath)
@@ -2088,13 +2100,11 @@ void zen::synchronize(const TimeComp& timeStamp,
 
         if (folderPairCfg.handleDeletion == DeletionPolicy::RECYCLER)
         {
-            if (folderPairStat.updateCount<LEFT_SIDE>() +
-                folderPairStat.deleteCount<LEFT_SIDE>() > 0)
-                checkRecycler(j->getAbstractPath<LEFT_SIDE>());
+            if (folderPairStat.expectPhysicalDeletion<LEFT_SIDE>())
+                checkRecycler(baseFolder.getAbstractPath<LEFT_SIDE>());
 
-            if (folderPairStat.updateCount<RIGHT_SIDE>() +
-                folderPairStat.deleteCount<RIGHT_SIDE>() > 0)
-                checkRecycler(j->getAbstractPath<RIGHT_SIDE>());
+            if (folderPairStat.expectPhysicalDeletion<RIGHT_SIDE>())
+                checkRecycler(baseFolder.getAbstractPath<RIGHT_SIDE>());
         }
     }
 
@@ -2104,7 +2114,7 @@ void zen::synchronize(const TimeComp& timeStamp,
         std::wstring msg = _("The following items have unresolved conflicts and will not be synchronized:");
 
         for (const SyncStatistics::ConflictInfo& item : unresolvedConflicts) //show *all* conflicts in warning message
-            msg += L"\n\n" + fmtPath(item.first) + L": " + item.second;
+            msg += L"\n\n" + fmtPath(item.relPath) + L": " + item.msg;
 
         callback.reportWarning(msg, warnings.warningUnresolvedConflicts);
     }
@@ -2176,9 +2186,10 @@ void zen::synchronize(const TimeComp& timeStamp,
     try
     {
         //loop through all directory pairs
-        for (auto j = begin(folderCmp); j != end(folderCmp); ++j)
+        for (auto itBase = begin(folderCmp); itBase != end(folderCmp); ++itBase)
         {
-            const size_t folderIndex = j - begin(folderCmp);
+            BaseFolderPair& baseFolder = *itBase;
+            const size_t folderIndex = itBase - begin(folderCmp);
             const FolderPairSyncCfg& folderPairCfg  = syncConfig     [folderIndex];
             const SyncStatistics&    folderPairStat = folderPairStats[folderIndex];
 
@@ -2187,19 +2198,19 @@ void zen::synchronize(const TimeComp& timeStamp,
 
             //------------------------------------------------------------------------------------------
             callback.reportInfo(_("Synchronizing folder pair:") + L" [" + getVariantName(folderPairCfg.syncVariant_) + L"]\n" +
-                                L"    " + AFS::getDisplayPath(j->getAbstractPath< LEFT_SIDE>()) + L"\n" +
-                                L"    " + AFS::getDisplayPath(j->getAbstractPath<RIGHT_SIDE>()));
+                                L"    " + AFS::getDisplayPath(baseFolder.getAbstractPath< LEFT_SIDE>()) + L"\n" +
+                                L"    " + AFS::getDisplayPath(baseFolder.getAbstractPath<RIGHT_SIDE>()));
             //------------------------------------------------------------------------------------------
 
             //checking a second time: (a long time may have passed since the intro checks!)
-            if (baseFolderDrop< LEFT_SIDE>(*j, folderAccessTimeout, callback) ||
-                baseFolderDrop<RIGHT_SIDE>(*j, folderAccessTimeout, callback))
+            if (baseFolderDrop< LEFT_SIDE>(baseFolder, folderAccessTimeout, callback) ||
+                baseFolderDrop<RIGHT_SIDE>(baseFolder, folderAccessTimeout, callback))
                 continue;
 
             //create base folders if not yet existing
             if (folderPairStat.createCount() > 0 || folderPairCfg.saveSyncDB_) //else: temporary network drop leading to deletions already caught by "sourceFolderMissing" check!
-                if (!createBaseFolder< LEFT_SIDE>(*j, callback) || //+ detect temporary network drop!!
-                    !createBaseFolder<RIGHT_SIDE>(*j, callback))   //
+                if (!createBaseFolder< LEFT_SIDE>(baseFolder, callback) || //+ detect temporary network drop!!
+                    !createBaseFolder<RIGHT_SIDE>(baseFolder, callback))   //
                     continue;
 
             //------------------------------------------------------------------------------------------
@@ -2211,7 +2222,7 @@ void zen::synchronize(const TimeComp& timeStamp,
                 try
             {
                 if (folderPairCfg.saveSyncDB_)
-                    zen::saveLastSynchronousState(*j, nullptr);
+                    zen::saveLastSynchronousState(baseFolder, nullptr);
             } //throw FileError
             catch (FileError&) {}
             );
@@ -2219,15 +2230,16 @@ void zen::synchronize(const TimeComp& timeStamp,
             if (jobType[folderIndex] == FolderPairJobType::PROCESS)
             {
                 //guarantee removal of invalid entries (where element is empty on both sides)
-                ZEN_ON_SCOPE_EXIT(BaseFolderPair::removeEmpty(*j));
+                ZEN_ON_SCOPE_EXIT(BaseFolderPair::removeEmpty(baseFolder));
 
                 bool copyPermissionsFp = false;
                 tryReportingError([&]
                 {
                     copyPermissionsFp = copyFilePermissions && //copy permissions only if asked for and supported by *both* sides!
-                    !AFS::isNullPath(j->getAbstractPath< LEFT_SIDE>()) && //scenario: directory selected on one side only
-                    !AFS::isNullPath(j->getAbstractPath<RIGHT_SIDE>()) && //
-                    AFS::supportPermissionCopy(j->getAbstractPath<LEFT_SIDE>(), j->getAbstractPath<RIGHT_SIDE>()); //throw FileError
+                    !AFS::isNullPath(baseFolder.getAbstractPath< LEFT_SIDE>()) && //scenario: directory selected on one side only
+                    !AFS::isNullPath(baseFolder.getAbstractPath<RIGHT_SIDE>()) && //
+                    AFS::supportPermissionCopy(baseFolder.getAbstractPath<LEFT_SIDE>(),
+                    baseFolder.getAbstractPath<RIGHT_SIDE>()); //throw FileError
                 }, callback); //throw X?
 
 
@@ -2244,15 +2256,15 @@ void zen::synchronize(const TimeComp& timeStamp,
                 };
 
 
-                DeletionHandling delHandlerL(j->getAbstractPath<LEFT_SIDE>(),
-                                             getEffectiveDeletionPolicy(j->getAbstractPath<LEFT_SIDE>()),
+                DeletionHandling delHandlerL(baseFolder.getAbstractPath<LEFT_SIDE>(),
+                                             getEffectiveDeletionPolicy(baseFolder.getAbstractPath<LEFT_SIDE>()),
                                              folderPairCfg.versioningFolderPhrase,
                                              folderPairCfg.versioningStyle_,
                                              timeStamp,
                                              callback);
 
-                DeletionHandling delHandlerR(j->getAbstractPath<RIGHT_SIDE>(),
-                                             getEffectiveDeletionPolicy(j->getAbstractPath<RIGHT_SIDE>()),
+                DeletionHandling delHandlerR(baseFolder.getAbstractPath<RIGHT_SIDE>(),
+                                             getEffectiveDeletionPolicy(baseFolder.getAbstractPath<RIGHT_SIDE>()),
                                              folderPairCfg.versioningFolderPhrase,
                                              folderPairCfg.versioningStyle_,
                                              timeStamp,
@@ -2264,7 +2276,7 @@ void zen::synchronize(const TimeComp& timeStamp,
                                              shadowCopyHandler.get(),
 #endif
                                              delHandlerL, delHandlerR);
-                syncFP.startSync(*j);
+                syncFP.startSync(baseFolder);
 
                 //(try to gracefully) cleanup temporary Recycle bin folders and versioning -> will be done in ~DeletionHandling anyway...
                 tryReportingError([&] { delHandlerL.tryCleanup(true /*allowUserCallback*/); /*throw FileError*/}, callback); //throw X?
@@ -2282,7 +2294,7 @@ void zen::synchronize(const TimeComp& timeStamp,
                 tryReportingError([&]
                 {
                     std::int64_t bytesWritten = 0;
-                    zen::saveLastSynchronousState(*j, [&](std::int64_t bytesDelta) //throw FileError
+                    zen::saveLastSynchronousState(baseFolder, [&](std::int64_t bytesDelta) //throw FileError
                     {
                         bytesWritten += bytesDelta;
                         callback.reportStatus(dbUpdateMsg + L" (" + filesizeToShortString(bytesWritten) + L")"); //throw X
diff --git a/FreeFileSync/Source/synchronization.h b/FreeFileSync/Source/synchronization.h
index db9b3308..3992cda0 100644
--- a/FreeFileSync/Source/synchronization.h
+++ b/FreeFileSync/Source/synchronization.h
@@ -35,12 +35,19 @@ public:
     int deleteCount() const { return SelectParam<side>::ref(deleteLeft_, deleteRight_); }
     int deleteCount() const { return deleteLeft_ + deleteRight_; }
 
+    template <SelectedSide side>
+    bool expectPhysicalDeletion() const { return SelectParam<side>::ref(physicalDeleteLeft_, physicalDeleteRight_); }
+
     int conflictCount() const { return static_cast<int>(conflictMsgs_.size()); }
 
     std::int64_t getBytesToProcess() const { return bytesToProcess_; }
     size_t       rowCount         () const { return rowsTotal_; }
 
-    using ConflictInfo = std::pair<Zstring, std::wstring>; //pair(filePath/conflict message)
+    struct ConflictInfo
+    {
+        Zstring relPath;
+        std::wstring msg;
+    };
     const std::vector<ConflictInfo>& getConflicts() const { return conflictMsgs_; }
 
 private:
@@ -56,6 +63,8 @@ private:
     int updateRight_ = 0;
     int deleteLeft_  = 0;
     int deleteRight_ = 0;
+    bool physicalDeleteLeft_  = false; //at least 1 item will be deleted; considers most "update" cases which also delete items
+    bool physicalDeleteRight_ = false; //
     std::vector<ConflictInfo> conflictMsgs_; //conflict texts to display as a warning message
     std::int64_t bytesToProcess_ = 0;
     size_t rowsTotal_ = 0;
diff --git a/FreeFileSync/Source/ui/batch_status_handler.cpp b/FreeFileSync/Source/ui/batch_status_handler.cpp
index d9438dd4..76fe7b10 100644
--- a/FreeFileSync/Source/ui/batch_status_handler.cpp
+++ b/FreeFileSync/Source/ui/batch_status_handler.cpp
@@ -6,6 +6,7 @@
 
 #include "batch_status_handler.h"
 #include <zen/shell_execute.h>
+#include <zen/thread.h>
 #include <wx+/popup_dlg.h>
 #include <wx/app.h>
 #include "on_completion_box.h"
@@ -143,25 +144,22 @@ BatchStatusHandler::BatchStatusHandler(bool showProgress,
                                        const xmlAccess::OnError handleError,
                                        size_t automaticRetryCount,
                                        size_t automaticRetryDelay,
-                                       const SwitchToGui& switchBatchToGui, //functionality to change from batch mode to GUI mode
                                        FfsReturnCode& returnCode,
                                        const Zstring& onCompletion,
                                        std::vector<Zstring>& onCompletionHistory) :
-    switchBatchToGui_(switchBatchToGui),
-    showFinalResults(showProgress), //=> exit immediately or wait when finished
+    showFinalResults_(showProgress), //=> exit immediately or wait when finished
     logfilesCountLimit_(logfilesCountLimit),
     lastSyncsLogFileSizeMax_(lastSyncsLogFileSizeMax),
     handleError_(handleError),
     returnCode_(returnCode),
     automaticRetryCount_(automaticRetryCount),
     automaticRetryDelay_(automaticRetryDelay),
-    progressDlg(createProgressDialog(*this, [this] { this->onProgressDialogTerminate(); }, *this, nullptr, showProgress, jobName, soundFileSyncComplete, onCompletion, onCompletionHistory)),
-            jobName_(jobName),
-            timeStamp_(timeStamp),
-            startTime_(std::time(nullptr)),
-            logFolderPathPhrase_(logFolderPathPhrase)
+    progressDlg_(createProgressDialog(*this, [this] { this->onProgressDialogTerminate(); }, *this, nullptr, showProgress, jobName, soundFileSyncComplete, onCompletion, onCompletionHistory)),
+             jobName_(jobName),
+             timeStamp_(timeStamp),
+             logFolderPathPhrase_(logFolderPathPhrase)
 {
-    //ATTENTION: "progressDlg" is an unmanaged resource!!! However, at this point we already consider construction complete! =>
+    //ATTENTION: "progressDlg_" is an unmanaged resource!!! However, at this point we already consider construction complete! =>
     //ZEN_ON_SCOPE_FAIL( cleanup(); ); //destructor call would lead to member double clean-up!!!
 
     //...
@@ -176,28 +174,21 @@ BatchStatusHandler::~BatchStatusHandler()
     //------------ "on completion" command conceptually is part of the sync, not cleanup --------------------------------------
 
     //decide whether to stay on status screen or exit immediately...
-    if (switchToGuiRequested) //-> avoid recursive yield() calls, thous switch not before ending batch mode
+    if (progressDlg_)
     {
-        try
-        {
-            switchBatchToGui_.execute(); //open FreeFileSync GUI
-        }
-        catch (...) { assert(false); }
-        showFinalResults = false;
-    }
-    else if (progressDlg)
-    {
-        if (progressDlg->getWindowIfVisible())
-            showFinalResults = true;
+        if (switchToGuiRequested_) //-> avoid recursive yield() calls, thous switch not before ending batch mode
+            showFinalResults_ = false;
+        else if (progressDlg_->getWindowIfVisible())
+            showFinalResults_ = true;
 
         //execute "on completion" command (even in case of ignored errors)
         if (!abortIsRequested()) //if aborted (manually), we don't execute the command
         {
-            const Zstring finalCommand = progressDlg->getExecWhenFinishedCommand(); //final value (after possible user modification)
+            const Zstring finalCommand = progressDlg_->getExecWhenFinishedCommand(); //final value (after possible user modification)
             if (!finalCommand.empty())
             {
                 if (isCloseProgressDlgCommand(finalCommand))
-                    showFinalResults = false; //take precedence over current visibility status
+                    showFinalResults_ = false; //take precedence over current visibility status
                 else
                     try
                     {
@@ -211,8 +202,8 @@ BatchStatusHandler::~BatchStatusHandler()
     }
     //------------ end of sync: begin of cleanup --------------------------------------
 
-    const int totalErrors   = errorLog.getItemCount(TYPE_ERROR | TYPE_FATAL_ERROR); //evaluate before finalizing log
-    const int totalWarnings = errorLog.getItemCount(TYPE_WARNING);
+    const int totalErrors   = errorLog_.getItemCount(TYPE_ERROR | TYPE_FATAL_ERROR); //evaluate before finalizing log
+    const int totalWarnings = errorLog_.getItemCount(TYPE_WARNING);
 
     //finalize error log
     std::wstring status; //additionally indicate errors in log file name
@@ -221,21 +212,21 @@ BatchStatusHandler::~BatchStatusHandler()
     {
         raiseReturnCode(returnCode_, FFS_RC_ABORTED);
         finalStatusMsg = _("Synchronization stopped");
-        errorLog.logMsg(finalStatusMsg, TYPE_ERROR);
+        errorLog_.logMsg(finalStatusMsg, TYPE_ERROR);
         status = _("Stopped");
     }
     else if (totalErrors > 0)
     {
         raiseReturnCode(returnCode_, FFS_RC_FINISHED_WITH_ERRORS);
         finalStatusMsg = _("Synchronization completed with errors");
-        errorLog.logMsg(finalStatusMsg, TYPE_ERROR);
+        errorLog_.logMsg(finalStatusMsg, TYPE_ERROR);
         status = _("Error");
     }
     else if (totalWarnings > 0)
     {
         raiseReturnCode(returnCode_, FFS_RC_FINISHED_WITH_WARNINGS);
         finalStatusMsg = _("Synchronization completed with warnings");
-        errorLog.logMsg(finalStatusMsg, TYPE_WARNING);
+        errorLog_.logMsg(finalStatusMsg, TYPE_WARNING);
         status = _("Warning");
     }
     else
@@ -245,7 +236,7 @@ BatchStatusHandler::~BatchStatusHandler()
             finalStatusMsg = _("Nothing to synchronize"); //even if "ignored conflicts" occurred!
         else
             finalStatusMsg = _("Synchronization completed successfully");
-        errorLog.logMsg(finalStatusMsg, TYPE_INFO);
+        errorLog_.logMsg(finalStatusMsg, TYPE_INFO);
     }
 
     const SummaryInfo summary =
@@ -263,7 +254,7 @@ BatchStatusHandler::~BatchStatusHandler()
     {
         auto requestUiRefreshNoThrow = [&] { try { requestUiRefresh();  /*throw X*/ } catch (...) {} };
 
-        const AbstractPath logFolderPath = createAbstractPath(trimCpy(logFolderPathPhrase_).empty() ? getConfigDir() + Zstr("Logs") : logFolderPathPhrase_); //noexcept
+        const AbstractPath logFolderPath = createAbstractPath(trimCpy(logFolderPathPhrase_).empty() ? getConfigDirPathPf() + Zstr("Logs") : logFolderPathPhrase_); //noexcept
         try
         {
             tryReportingError([&] //errors logged here do not impact final status calculation above! => not a problem!
@@ -272,7 +263,7 @@ BatchStatusHandler::~BatchStatusHandler()
                 AFS::OutputStream& logFileStream = *rv.first;
                 const AbstractPath logFilePath   = rv.second;
 
-                streamToLogFile(summary, errorLog, logFileStream, OnUpdateLogfileStatusNoThrow(*this, AFS::getDisplayPath(logFilePath))); //throw FileError
+                streamToLogFile(summary, errorLog_, logFileStream, OnUpdateLogfileStatusNoThrow(*this, AFS::getDisplayPath(logFilePath))); //throw FileError
                 logFileStream.finalize(requestUiRefreshNoThrow); //throw FileError
             }, *this); //throw X?
         }
@@ -296,37 +287,37 @@ BatchStatusHandler::~BatchStatusHandler()
     //----------------- write results into LastSyncs.log------------------------
     try
     {
-        saveToLastSyncsLog(summary, errorLog, lastSyncsLogFileSizeMax_, OnUpdateLogfileStatusNoThrow(*this, utfCvrtTo<std::wstring>(getLastSyncsLogfilePath()))); //throw FileError
+        saveToLastSyncsLog(summary, errorLog_, lastSyncsLogFileSizeMax_, OnUpdateLogfileStatusNoThrow(*this, utfCvrtTo<std::wstring>(getLastSyncsLogfilePath()))); //throw FileError
     }
     catch (FileError&) { assert(false); }
 
-    if (progressDlg)
+    if (progressDlg_)
     {
-        if (showFinalResults) //warning: wxWindow::Show() is called within processHasFinished()!
+        if (showFinalResults_) //warning: wxWindow::Show() is called within processHasFinished()!
         {
             //notify about (logical) application main window => program won't quit, but stay on this dialog
-            //setMainWindow(progressDlg->getAsWindow()); -> not required anymore since we block waiting until dialog is closed below
+            //setMainWindow(progressDlg_->getAsWindow()); -> not required anymore since we block waiting until dialog is closed below
 
-            //notify to progressDlg that current process has ended
+            //notify to progressDlg_ that current process has ended
             if (abortIsRequested())
-                progressDlg->processHasFinished(SyncProgressDialog::RESULT_ABORTED, errorLog); //enable okay and close events
+                progressDlg_->processHasFinished(SyncProgressDialog::RESULT_ABORTED, errorLog_); //enable okay and close events
             else if (totalErrors > 0)
-                progressDlg->processHasFinished(SyncProgressDialog::RESULT_FINISHED_WITH_ERROR, errorLog);
+                progressDlg_->processHasFinished(SyncProgressDialog::RESULT_FINISHED_WITH_ERROR, errorLog_);
             else if (totalWarnings > 0)
-                progressDlg->processHasFinished(SyncProgressDialog::RESULT_FINISHED_WITH_WARNINGS, errorLog);
+                progressDlg_->processHasFinished(SyncProgressDialog::RESULT_FINISHED_WITH_WARNINGS, errorLog_);
             else
-                progressDlg->processHasFinished(SyncProgressDialog::RESULT_FINISHED_WITH_SUCCESS, errorLog);
+                progressDlg_->processHasFinished(SyncProgressDialog::RESULT_FINISHED_WITH_SUCCESS, errorLog_);
         }
         else
-            progressDlg->closeWindowDirectly(); //progressDlg is main window => program will quit directly
+            progressDlg_->closeWindowDirectly(); //progressDlg_ is main window => program will quit directly
 
         //wait until progress dialog notified shutdown via onProgressDialogTerminate()
         //-> required since it has our "this" pointer captured in lambda "notifyWindowTerminate"!
         //-> nicely manages dialog lifetime
-        while (progressDlg)
+        while (progressDlg_)
         {
             wxTheApp->Yield(); //*first* refresh GUI (removing flicker) before sleeping!
-            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL));
+            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS));
         }
     }
 }
@@ -335,8 +326,8 @@ BatchStatusHandler::~BatchStatusHandler()
 void BatchStatusHandler::initNewPhase(int itemsTotal, std::int64_t bytesTotal, ProcessCallback::Phase phaseID)
 {
     StatusHandler::initNewPhase(itemsTotal, bytesTotal, phaseID);
-    if (progressDlg)
-        progressDlg->initNewPhase(); //call after "StatusHandler::initNewPhase"
+    if (progressDlg_)
+        progressDlg_->initNewPhase(); //call after "StatusHandler::initNewPhase"
 
     forceUiRefresh(); //throw ?; OS X needs a full yield to update GUI and get rid of "dummy" texts
 }
@@ -346,8 +337,8 @@ void BatchStatusHandler::updateProcessedData(int itemsDelta, std::int64_t bytesD
 {
     StatusHandler::updateProcessedData(itemsDelta, bytesDelta);
 
-    if (progressDlg)
-        progressDlg->notifyProgressChange(); //noexcept
+    if (progressDlg_)
+        progressDlg_->notifyProgressChange(); //noexcept
     //note: this method should NOT throw in order to properly allow undoing setting of statistics!
 }
 
@@ -355,13 +346,13 @@ void BatchStatusHandler::updateProcessedData(int itemsDelta, std::int64_t bytesD
 void BatchStatusHandler::reportInfo(const std::wstring& text)
 {
     StatusHandler::reportInfo(text);
-    errorLog.logMsg(text, TYPE_INFO);
+    errorLog_.logMsg(text, TYPE_INFO);
 }
 
 
 void BatchStatusHandler::reportWarning(const std::wstring& warningMessage, bool& warningActive)
 {
-    errorLog.logMsg(warningMessage, TYPE_WARNING);
+    errorLog_.logMsg(warningMessage, TYPE_WARNING);
 
     if (!warningActive)
         return;
@@ -370,12 +361,12 @@ void BatchStatusHandler::reportWarning(const std::wstring& warningMessage, bool&
     {
         case xmlAccess::ON_ERROR_POPUP:
         {
-            if (!progressDlg) abortProcessNow();
-            PauseTimers dummy(*progressDlg);
+            if (!progressDlg_) abortProcessNow();
+            PauseTimers dummy(*progressDlg_);
             forceUiRefresh();
 
             bool dontWarnAgain = false;
-            switch (showConfirmationDialog3(progressDlg->getWindowIfVisible(), DialogInfoType::WARNING, PopupDialogCfg3().
+            switch (showConfirmationDialog3(progressDlg_->getWindowIfVisible(), DialogInfoType::WARNING, PopupDialogCfg3().
                                             setDetailInstructions(warningMessage + L"\n\n" + _("You can switch to FreeFileSync's main window to resolve this issue.")).
                                             setCheckBox(dontWarnAgain, _("&Don't show this warning again"), ConfirmationButton3::DONT_DO_IT),
                                             _("&Ignore"), _("&Switch")))
@@ -385,10 +376,10 @@ void BatchStatusHandler::reportWarning(const std::wstring& warningMessage, bool&
                     break;
 
                 case ConfirmationButton3::DONT_DO_IT: //switch
-                    errorLog.logMsg(_("Switching to FreeFileSync's main window"), TYPE_INFO);
-                    switchToGuiRequested = true;
-                    abortProcessNow();
-                    break;
+                    errorLog_.logMsg(_("Switching to FreeFileSync's main window"), TYPE_INFO);
+                    switchToGuiRequested_ = true; //treat as a special kind of cancel
+                    requestAbortion();            //
+                    throw BatchRequestSwitchToMainDialog();
 
                 case ConfirmationButton3::CANCEL:
                     abortProcessNow();
@@ -412,33 +403,33 @@ ProcessCallback::Response BatchStatusHandler::reportError(const std::wstring& er
     //auto-retry
     if (retryNumber < automaticRetryCount_)
     {
-        errorLog.logMsg(errorMessage + L"\n-> " +
-                        _P("Automatic retry in 1 second...", "Automatic retry in %x seconds...", automaticRetryDelay_), TYPE_INFO);
+        errorLog_.logMsg(errorMessage + L"\n-> " +
+                         _P("Automatic retry in 1 second...", "Automatic retry in %x seconds...", automaticRetryDelay_), TYPE_INFO);
         //delay
-        const int iterations = static_cast<int>(1000 * automaticRetryDelay_ / UI_UPDATE_INTERVAL); //always round down: don't allow for negative remaining time below
+        const int iterations = static_cast<int>(1000 * automaticRetryDelay_ / UI_UPDATE_INTERVAL_MS); //always round down: don't allow for negative remaining time below
         for (int i = 0; i < iterations; ++i)
         {
             reportStatus(_("Error") + L": " + _P("Automatic retry in 1 second...", "Automatic retry in %x seconds...",
-                                                 (1000 * automaticRetryDelay_ - i * UI_UPDATE_INTERVAL + 999) / 1000)); //integer round up
-            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL));
+                                                 (1000 * automaticRetryDelay_ - i * UI_UPDATE_INTERVAL_MS + 999) / 1000)); //integer round up
+            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS));
         }
         return ProcessCallback::RETRY;
     }
 
 
     //always, except for "retry":
-    auto guardWriteLog = zen::makeGuard<ScopeGuardRunMode::ON_EXIT>([&] { errorLog.logMsg(errorMessage, TYPE_ERROR); });
+    auto guardWriteLog = zen::makeGuard<ScopeGuardRunMode::ON_EXIT>([&] { errorLog_.logMsg(errorMessage, TYPE_ERROR); });
 
     switch (handleError_)
     {
         case xmlAccess::ON_ERROR_POPUP:
         {
-            if (!progressDlg) abortProcessNow();
-            PauseTimers dummy(*progressDlg);
+            if (!progressDlg_) abortProcessNow();
+            PauseTimers dummy(*progressDlg_);
             forceUiRefresh();
 
             bool ignoreNextErrors = false;
-            switch (showConfirmationDialog3(progressDlg->getWindowIfVisible(), DialogInfoType::ERROR2, PopupDialogCfg3().
+            switch (showConfirmationDialog3(progressDlg_->getWindowIfVisible(), DialogInfoType::ERROR2, PopupDialogCfg3().
                                             setDetailInstructions(errorMessage).
                                             setCheckBox(ignoreNextErrors, _("&Ignore subsequent errors"), ConfirmationButton3::DONT_DO_IT),
                                             _("&Ignore"), _("&Retry")))
@@ -450,7 +441,7 @@ ProcessCallback::Response BatchStatusHandler::reportError(const std::wstring& er
 
                 case ConfirmationButton3::DONT_DO_IT: //retry
                     guardWriteLog.dismiss();
-                    errorLog.logMsg(errorMessage + L"\n-> " + _("Retrying operation..."), TYPE_INFO);
+                    errorLog_.logMsg(errorMessage + L"\n-> " + _("Retrying operation..."), TYPE_INFO);
                     return ProcessCallback::RETRY;
 
                 case ConfirmationButton3::CANCEL:
@@ -475,18 +466,18 @@ ProcessCallback::Response BatchStatusHandler::reportError(const std::wstring& er
 
 void BatchStatusHandler::reportFatalError(const std::wstring& errorMessage)
 {
-    errorLog.logMsg(errorMessage, TYPE_FATAL_ERROR);
+    errorLog_.logMsg(errorMessage, TYPE_FATAL_ERROR);
 
     switch (handleError_)
     {
         case xmlAccess::ON_ERROR_POPUP:
         {
-            if (!progressDlg) abortProcessNow();
-            PauseTimers dummy(*progressDlg);
+            if (!progressDlg_) abortProcessNow();
+            PauseTimers dummy(*progressDlg_);
             forceUiRefresh();
 
             bool ignoreNextErrors = false;
-            switch (showConfirmationDialog(progressDlg->getWindowIfVisible(), DialogInfoType::ERROR2,
+            switch (showConfirmationDialog(progressDlg_->getWindowIfVisible(), DialogInfoType::ERROR2,
                                            PopupDialogCfg().setTitle(_("Serious Error")).
                                            setDetailInstructions(errorMessage).
                                            setCheckBox(ignoreNextErrors, _("&Ignore subsequent errors")),
@@ -515,20 +506,20 @@ void BatchStatusHandler::reportFatalError(const std::wstring& errorMessage)
 
 void BatchStatusHandler::forceUiRefresh()
 {
-    if (progressDlg)
-        progressDlg->updateGui();
+    if (progressDlg_)
+        progressDlg_->updateGui();
 }
 
 
 void BatchStatusHandler::abortProcessNow()
 {
     requestAbortion(); //just make sure...
-    throw BatchAbortProcess(); //abort can be triggered by progressDlg
+    throw BatchAbortProcess(); //abort can be triggered by progressDlg_
 }
 
 
 void BatchStatusHandler::onProgressDialogTerminate()
 {
-    //it's responsibility of "progressDlg" to call requestAbortion() when closing dialog
-    progressDlg = nullptr;
+    //it's responsibility of "progressDlg_" to call requestAbortion() when closing dialog
+    progressDlg_ = nullptr;
 }
diff --git a/FreeFileSync/Source/ui/batch_status_handler.h b/FreeFileSync/Source/ui/batch_status_handler.h
index 774f230d..27ace6ee 100644
--- a/FreeFileSync/Source/ui/batch_status_handler.h
+++ b/FreeFileSync/Source/ui/batch_status_handler.h
@@ -10,18 +10,17 @@
 #include <zen/error_log.h>
 #include <zen/time.h>
 #include "progress_indicator.h"
-#include "switch_to_gui.h"
 #include "../lib/status_handler.h"
 #include "../lib/process_xml.h"
 #include "../lib/return_codes.h"
 
 
-//Exception class used to abort the "compare" and "sync" process
+//Exception classes used to abort the "compare" and "sync" process
 class BatchAbortProcess {};
-
+class BatchRequestSwitchToMainDialog {};
 
 //BatchStatusHandler(SyncProgressDialog) will internally process Window messages! disable GUI controls to avoid unexpected callbacks!
-class BatchStatusHandler : public zen::StatusHandler //throw BatchAbortProcess
+class BatchStatusHandler : public zen::StatusHandler //throw BatchAbortProcess, BatchRequestSwitchToMainDialog
 {
 public:
     BatchStatusHandler(bool showProgress, //defines: -start minimized and -quit immediately when finished
@@ -34,7 +33,6 @@ public:
                        const xmlAccess::OnError handleError,
                        size_t automaticRetryCount,
                        size_t automaticRetryDelay,
-                       const zen::SwitchToGui& switchBatchToGui, //functionality to change from batch mode to GUI mode
                        zen::FfsReturnCode& returnCode,
                        const Zstring& onCompletion,
                        std::vector<Zstring>& onCompletionHistory);
@@ -54,23 +52,22 @@ public:
 private:
     void onProgressDialogTerminate();
 
-    const zen::SwitchToGui& switchBatchToGui_; //functionality to change from batch mode to GUI mode
-    bool showFinalResults;
-    bool switchToGuiRequested = false;
+    bool showFinalResults_;
+    bool switchToGuiRequested_ = false;
     const int logfilesCountLimit_;
     const size_t lastSyncsLogFileSizeMax_;
     xmlAccess::OnError handleError_;
-    zen::ErrorLog errorLog; //list of non-resolved errors and warnings
+    zen::ErrorLog errorLog_; //list of non-resolved errors and warnings
     zen::FfsReturnCode& returnCode_;
 
     const size_t automaticRetryCount_;
     const size_t automaticRetryDelay_;
 
-    SyncProgressDialog* progressDlg; //managed to have shorter lifetime than this handler!
+    SyncProgressDialog* progressDlg_; //managed to have shorter lifetime than this handler!
 
     const std::wstring jobName_;
     const zen::TimeComp timeStamp_;
-    const time_t startTime_; //don't use wxStopWatch: may overflow after a few days due to ::QueryPerformanceCounter()
+    const time_t startTime_ = std::time(nullptr); //don't use wxStopWatch: may overflow after a few days due to ::QueryPerformanceCounter()
 
     const Zstring logFolderPathPhrase_;
 };
diff --git a/FreeFileSync/Source/ui/column_attr.h b/FreeFileSync/Source/ui/column_attr.h
index d48640bc..2f8daf5f 100644
--- a/FreeFileSync/Source/ui/column_attr.h
+++ b/FreeFileSync/Source/ui/column_attr.h
@@ -16,7 +16,7 @@ enum class ColumnTypeRim
     ITEM_PATH,
     SIZE,
     DATE,
-    EXTENSION
+    EXTENSION,
 };
 
 struct ColumnAttributeRim
@@ -33,12 +33,12 @@ struct ColumnAttributeRim
 inline
 std::vector<ColumnAttributeRim> getDefaultColumnAttributesLeft()
 {
-    return
+    return //harmonize with main_dlg.cpp::onGridLabelContextRim() => expects stretched ITEM_PATH and non-stretched other columns!
     {
         { ColumnTypeRim::ITEM_PATH, -80, 1, true  }, //stretch to full width and substract sum of fixed-size widths!
+        { ColumnTypeRim::EXTENSION,  60, 0, false },
         { ColumnTypeRim::DATE,      112, 0, false },
         { ColumnTypeRim::SIZE,       80, 0, true  },
-        { ColumnTypeRim::EXTENSION,  60, 0, false },
     };
 }
 
@@ -48,9 +48,9 @@ std::vector<ColumnAttributeRim> getDefaultColumnAttributesRight()
     return
     {
         { ColumnTypeRim::ITEM_PATH, -80, 1, true  },
+        { ColumnTypeRim::EXTENSION,  60, 0, false },
         { ColumnTypeRim::DATE,      112, 0, false },
         { ColumnTypeRim::SIZE,       80, 0, true  },
-        { ColumnTypeRim::EXTENSION,  60, 0, false },
     };
 }
 
@@ -58,7 +58,7 @@ enum class ItemPathFormat
 {
     FULL_PATH,
     RELATIVE_PATH,
-    ITEM_NAME
+    ITEM_NAME,
 };
 
 const ItemPathFormat defaultItemPathFormatLeftGrid  = ItemPathFormat::RELATIVE_PATH;
@@ -77,9 +77,9 @@ enum class ColumnTypeCenter
 
 enum class ColumnTypeNavi
 {
+    FOLDER_NAME,
+    ITEM_COUNT,
     BYTES,
-    DIRECTORY,
-    ITEM_COUNT
 };
 
 struct ColumnAttributeNavi
@@ -87,7 +87,7 @@ struct ColumnAttributeNavi
     ColumnAttributeNavi() {}
     ColumnAttributeNavi(ColumnTypeNavi type, int offset, int stretch, bool visible) : type_(type), offset_(offset), stretch_(stretch), visible_(visible) {}
 
-    ColumnTypeNavi type_    = ColumnTypeNavi::DIRECTORY;
+    ColumnTypeNavi type_    = ColumnTypeNavi::FOLDER_NAME;
     int            offset_  = 0;
     int            stretch_ = 0;;
     bool           visible_ = false;
@@ -97,17 +97,17 @@ struct ColumnAttributeNavi
 inline
 std::vector<ColumnAttributeNavi> getDefaultColumnAttributesNavi()
 {
-    return
+    return //harmonize with tree_view.cpp::onGridLabelContext() => expects stretched FOLDER_NAME and non-stretched other columns!
     {
-        { ColumnTypeNavi::DIRECTORY, -120, 1, true }, //stretch to full width and substract sum of fixed size widths
-        { ColumnTypeNavi::ITEM_COUNT,  60, 0, true },
-        { ColumnTypeNavi::BYTES,       60, 0, true }, //GTK needs a few pixels more width
+        { ColumnTypeNavi::FOLDER_NAME, -120, 1, true }, //stretch to full width and substract sum of fixed size widths
+        { ColumnTypeNavi::ITEM_COUNT,    60, 0, true },
+        { ColumnTypeNavi::BYTES,         60, 0, true }, //GTK needs a few pixels more width
     };
 }
 
-const           bool naviGridShowPercentageDefault = true;
-const ColumnTypeNavi naviGridLastSortColumnDefault = ColumnTypeNavi::BYTES; //remember sort on navigation panel
-const           bool naviGridLastSortAscendingDefault = false;              //
+const           bool naviGridShowPercentageDefault    = true;
+const ColumnTypeNavi naviGridLastSortColumnDefault    = ColumnTypeNavi::BYTES; //remember sort on navigation panel
+const           bool naviGridLastSortAscendingDefault = false;                 //
 }
 
 #endif //COLUMN_ATTR_H_189467891346732143213
diff --git a/FreeFileSync/Source/ui/custom_grid.cpp b/FreeFileSync/Source/ui/custom_grid.cpp
index 3d068b6b..b47e6de9 100644
--- a/FreeFileSync/Source/ui/custom_grid.cpp
+++ b/FreeFileSync/Source/ui/custom_grid.cpp
@@ -196,6 +196,29 @@ public:
 
     void setItemPathForm(ItemPathFormat fmt) { itemPathFormat = fmt; }
 
+    void getUnbufferedIconsForPreload(std::vector<std::pair<ptrdiff_t, AbstractPath>>& newLoad) //return (priority, filepath) list
+    {
+        if (iconMgr_)
+        {
+            const auto& rowsOnScreen = getVisibleRows(refGrid());
+            const ptrdiff_t visibleRowCount = rowsOnScreen.second - rowsOnScreen.first;
+
+            //preload icons not yet on screen:
+            const int preloadSize = 2 * std::max<ptrdiff_t>(20, visibleRowCount); //:= sum of lines above and below of visible range to preload
+            //=> use full visible height to handle "next page" command and a minimum of 20 for excessive mouse wheel scrolls
+
+            for (ptrdiff_t i = 0; i < preloadSize; ++i)
+            {
+                const ptrdiff_t currentRow = rowsOnScreen.first - (preloadSize + 1) / 2 + getAlternatingPos(i, visibleRowCount + preloadSize); //for odd preloadSize start one row earlier
+
+                const IconInfo ii = getIconInfo(currentRow);
+                if (ii.type == IconInfo::ICON_PATH)
+                    if (!iconMgr_->refIconBuffer().readyForRetrieval(ii.fsObj->template getAbstractPath<side>()))
+                        newLoad.emplace_back(i, ii.fsObj->template getAbstractPath<side>()); //insert least-important items on outer rim first
+            }
+        }
+    }
+
     void updateNewAndGetUnbufferedIcons(std::vector<AbstractPath>& newLoad) //loads all not yet drawn icons
     {
         if (iconMgr_)
@@ -229,29 +252,6 @@ public:
         }
     }
 
-    void getUnbufferedIconsForPreload(std::vector<std::pair<ptrdiff_t, AbstractPath>>& newLoad) //return (priority, filepath) list
-    {
-        if (iconMgr_)
-        {
-            const auto& rowsOnScreen = getVisibleRows(refGrid());
-            const ptrdiff_t visibleRowCount = rowsOnScreen.second - rowsOnScreen.first;
-
-            //preload icons not yet on screen:
-            const int preloadSize = 2 * std::max<ptrdiff_t>(20, visibleRowCount); //:= sum of lines above and below of visible range to preload
-            //=> use full visible height to handle "next page" command and a minimum of 20 for excessive mouse wheel scrolls
-
-            for (ptrdiff_t i = 0; i < preloadSize; ++i)
-            {
-                const ptrdiff_t currentRow = rowsOnScreen.first - (preloadSize + 1) / 2 + getAlternatingPos(i, visibleRowCount + preloadSize); //for odd preloadSize start one row earlier
-
-                const IconInfo ii = getIconInfo(currentRow);
-                if (ii.type == IconInfo::ICON_PATH)
-                    if (!iconMgr_->refIconBuffer().readyForRetrieval(ii.fsObj->template getAbstractPath<side>()))
-                        newLoad.emplace_back(i, ii.fsObj->template getAbstractPath<side>()); //insert least-important items on outer rim first
-            }
-        }
-    }
-
 private:
     bool isFailedLoad(size_t row) const { return row < failedLoads.size() ? failedLoads[row] != 0 : false; }
 
@@ -886,7 +886,7 @@ public:
                     }
         selectionInProgress = false;
 
-        //update highlight and tooltip: on OS X no mouse movement event is generated after a mouse button click (unlike on Windows)
+        //update highlight_ and tooltip: on OS X no mouse movement event is generated after a mouse button click (unlike on Windows)
         wxPoint clientPos = refGrid().getMainWin().ScreenToClient(wxGetMousePosition());
         onMouseMovement(clientPos);
     }
@@ -1635,14 +1635,14 @@ class IconUpdater : private wxEvtHandler //update file icons periodically: use S
 public:
     IconUpdater(GridDataLeft& provLeft, GridDataRight& provRight, IconBuffer& iconBuffer) : provLeft_(provLeft), provRight_(provRight), iconBuffer_(iconBuffer)
     {
-        timer.Connect(wxEVT_TIMER, wxEventHandler(IconUpdater::loadIconsAsynchronously), nullptr, this);
+        timer_.Connect(wxEVT_TIMER, wxEventHandler(IconUpdater::loadIconsAsynchronously), nullptr, this);
     }
 
-    void start() { if (!timer.IsRunning()) timer.Start(100); } //timer interval in [ms]
+    void start() { if (!timer_.IsRunning()) timer_.Start(100); } //timer interval in [ms]
     //don't check too often! give worker thread some time to fetch data
 
 private:
-    void stop() { if (timer.IsRunning()) timer.Stop(); }
+    void stop() { if (timer_.IsRunning()) timer_.Stop(); }
 
     void loadIconsAsynchronously(wxEvent& event) //loads all (not yet) drawn icons
     {
@@ -1671,7 +1671,7 @@ private:
     GridDataLeft& provLeft_;
     GridDataRight& provRight_;
     IconBuffer& iconBuffer_;
-    wxTimer timer;
+    wxTimer timer_;
 };
 
 
diff --git a/FreeFileSync/Source/ui/folder_selector.cpp b/FreeFileSync/Source/ui/folder_selector.cpp
index 52af6bd8..1e14634d 100644
--- a/FreeFileSync/Source/ui/folder_selector.cpp
+++ b/FreeFileSync/Source/ui/folder_selector.cpp
@@ -199,8 +199,8 @@ void FolderSelector::onFilesDropped(FileDropEvent& event)
 
         setPath(fmtShellPath(itemPaths[0]));
         //drop two folder paths at once:
-        if (siblingSelector && itemPaths.size() >= 2)
-            siblingSelector->setPath(fmtShellPath(itemPaths[1]));
+        if (siblingSelector_ && itemPaths.size() >= 2)
+            siblingSelector_->setPath(fmtShellPath(itemPaths[1]));
 
         //notify action invoked by user
         wxCommandEvent dummy(EVENT_ON_FOLDER_SELECTED);
diff --git a/FreeFileSync/Source/ui/folder_selector.h b/FreeFileSync/Source/ui/folder_selector.h
index f521747f..c504efa0 100644
--- a/FreeFileSync/Source/ui/folder_selector.h
+++ b/FreeFileSync/Source/ui/folder_selector.h
@@ -41,7 +41,7 @@ public:
 
     ~FolderSelector();
 
-    void setSiblingSelector(FolderSelector* selector) { siblingSelector = selector; }
+    void setSiblingSelector(FolderSelector* selector) { siblingSelector_ = selector; }
 
     Zstring getPath() const;
     void setPath(const Zstring& folderPathPhrase);
@@ -61,7 +61,7 @@ private:
     wxButton&         selectAltFolderButton_;
     FolderHistoryBox& folderComboBox_;
     wxStaticText*     staticText_ = nullptr; //optional
-    FolderSelector* siblingSelector = nullptr;
+    FolderSelector*   siblingSelector_ = nullptr;
 };
 }
 
diff --git a/FreeFileSync/Source/ui/gui_generated.cpp b/FreeFileSync/Source/ui/gui_generated.cpp
index 4ca60bbe..2683f6a4 100644
--- a/FreeFileSync/Source/ui/gui_generated.cpp
+++ b/FreeFileSync/Source/ui/gui_generated.cpp
@@ -80,9 +80,8 @@ MainDialogGenerated::MainDialogGenerated( wxWindow* parent, wxWindowID id, const
 
     m_menuTools->AppendSeparator();
 
-    wxMenuItem* m_menuItem15;
-    m_menuItem15 = new wxMenuItem( m_menuTools, wxID_FIND, wxString( _("&Find...") ) + wxT('\t') + wxT("Ctrl+F"), wxEmptyString, wxITEM_NORMAL );
-    m_menuTools->Append( m_menuItem15 );
+    m_menuItemFind = new wxMenuItem( m_menuTools, wxID_FIND, wxString( _("&Find...") ) + wxT('\t') + wxT("Ctrl+F"), wxEmptyString, wxITEM_NORMAL );
+    m_menuTools->Append( m_menuItemFind );
 
     wxMenuItem* m_menuItem51;
     m_menuItem51 = new wxMenuItem( m_menuTools, wxID_ANY, wxString( _("&Reset layout") ) , wxEmptyString, wxITEM_NORMAL );
@@ -98,16 +97,14 @@ MainDialogGenerated::MainDialogGenerated( wxWindow* parent, wxWindowID id, const
     m_menuItemHelp = new wxMenuItem( m_menuHelp, wxID_HELP, wxString( _("&View help") ) + wxT('\t') + wxT("F1"), wxEmptyString, wxITEM_NORMAL );
     m_menuHelp->Append( m_menuItemHelp );
 
-    m_menuCheckVersion = new wxMenu();
-    wxMenuItem* m_menuCheckVersionItem = new wxMenuItem( m_menuHelp, wxID_ANY, _("&Check for new version"), wxEmptyString, wxITEM_NORMAL, m_menuCheckVersion );
-    m_menuItemCheckVersionNow = new wxMenuItem( m_menuCheckVersion, wxID_ANY, wxString( _("&Check now") ) , wxEmptyString, wxITEM_NORMAL );
-    m_menuCheckVersion->Append( m_menuItemCheckVersionNow );
+    m_menuHelp->AppendSeparator();
 
-    m_menuItemCheckVersionAuto = new wxMenuItem( m_menuCheckVersion, wxID_ANY, wxString( _("Check &automatically once a week") ) , wxEmptyString, wxITEM_CHECK );
-    m_menuCheckVersion->Append( m_menuItemCheckVersionAuto );
-    m_menuItemCheckVersionAuto->Check( true );
+    m_menuItemCheckVersionNow = new wxMenuItem( m_menuHelp, wxID_ANY, wxString( _("&Check for updates now") ) , wxEmptyString, wxITEM_NORMAL );
+    m_menuHelp->Append( m_menuItemCheckVersionNow );
 
-    m_menuHelp->Append( m_menuCheckVersionItem );
+    m_menuItemCheckVersionAuto = new wxMenuItem( m_menuHelp, wxID_ANY, wxString( _("Check &automatically once a week") ) , wxEmptyString, wxITEM_CHECK );
+    m_menuHelp->Append( m_menuItemCheckVersionAuto );
+    m_menuItemCheckVersionAuto->Check( true );
 
     m_menuHelp->AppendSeparator();
 
@@ -973,7 +970,7 @@ MainDialogGenerated::MainDialogGenerated( wxWindow* parent, wxWindowID id, const
     this->Connect( m_menuItemSyncSettings->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnSyncSettings ) );
     this->Connect( m_menuItemSynchronize->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnStartSync ) );
     this->Connect( m_menuItemOptions->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnMenuOptions ) );
-    this->Connect( m_menuItem15->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnMenuFindItem ) );
+    this->Connect( m_menuItemFind->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnMenuFindItem ) );
     this->Connect( m_menuItem51->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnMenuResetLayout ) );
     this->Connect( m_menuItem5->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnMenuExportFileList ) );
     this->Connect( m_menuItemHelp->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler( MainDialogGenerated::OnShowHelp ) );
@@ -1246,7 +1243,7 @@ ConfigDlgGenerated::ConfigDlgGenerated( wxWindow* parent, wxWindowID id, const w
     m_panelCompSettingsHolder->SetSizer( bSizer275 );
     m_panelCompSettingsHolder->Layout();
     bSizer275->Fit( m_panelCompSettingsHolder );
-    m_notebook->AddPage( m_panelCompSettingsHolder, _("dummy"), false );
+    m_notebook->AddPage( m_panelCompSettingsHolder, _("dummy"), true );
     m_panelFilterSettingsHolder = new wxPanel( m_notebook, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL );
     m_panelFilterSettingsHolder->SetBackgroundColour( wxSystemSettings::GetColour( wxSYS_COLOUR_WINDOW ) );
 
@@ -1464,7 +1461,7 @@ ConfigDlgGenerated::ConfigDlgGenerated( wxWindow* parent, wxWindowID id, const w
     m_staticline46 = new wxStaticLine( m_panelFilterSettingsHolder, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_VERTICAL );
     bSizer280->Add( m_staticline46, 0, wxEXPAND, 5 );
 
-    m_buttonClear = new wxButton( m_panelFilterSettingsHolder, wxID_DEFAULT, _("C&lear"), wxDefaultPosition, wxSize( -1,-1 ), 0 );
+    m_buttonClear = new wxButton( m_panelFilterSettingsHolder, wxID_ANY, _("C&lear"), wxDefaultPosition, wxSize( -1,-1 ), 0 );
     bSizer280->Add( m_buttonClear, 0, wxALL|wxALIGN_CENTER_VERTICAL, 10 );
 
 
@@ -1761,22 +1758,22 @@ ConfigDlgGenerated::ConfigDlgGenerated( wxWindow* parent, wxWindowID id, const w
     m_staticText93->Wrap( -1 );
     bSizer198->Add( m_staticText93, 0, wxRIGHT|wxALIGN_CENTER_VERTICAL, 5 );
 
+    wxArrayString m_choiceVersioningStyleChoices;
+    m_choiceVersioningStyle = new wxChoice( m_panelVersioning, wxID_ANY, wxDefaultPosition, wxDefaultSize, m_choiceVersioningStyleChoices, 0 );
+    m_choiceVersioningStyle->SetSelection( 0 );
+    bSizer198->Add( m_choiceVersioningStyle, 0, wxALIGN_CENTER_VERTICAL, 5 );
+
 
     bSizer198->Add( 0, 0, 1, wxEXPAND, 5 );
 
     m_hyperlink17 = new wxHyperlinkCtrl( m_panelVersioning, wxID_ANY, _("Show examples"), wxEmptyString, wxDefaultPosition, wxDefaultSize, wxHL_DEFAULT_STYLE );
-    bSizer198->Add( m_hyperlink17, 0, 0, 5 );
+    bSizer198->Add( m_hyperlink17, 0, wxALIGN_CENTER_VERTICAL, 5 );
 
 
     bSizer191->Add( bSizer198, 0, wxEXPAND|wxBOTTOM|wxRIGHT|wxLEFT, 5 );
 
     bSizer192 = new wxBoxSizer( wxHORIZONTAL );
 
-    wxArrayString m_choiceVersioningStyleChoices;
-    m_choiceVersioningStyle = new wxChoice( m_panelVersioning, wxID_ANY, wxDefaultPosition, wxDefaultSize, m_choiceVersioningStyleChoices, 0 );
-    m_choiceVersioningStyle->SetSelection( 0 );
-    bSizer192->Add( m_choiceVersioningStyle, 0, wxALIGN_CENTER_VERTICAL|wxRIGHT, 5 );
-
     m_staticTextNamingCvtPart1 = new wxStaticText( m_panelVersioning, wxID_ANY, _("dummy"), wxDefaultPosition, wxDefaultSize, 0 );
     m_staticTextNamingCvtPart1->Wrap( -1 );
     m_staticTextNamingCvtPart1->SetForegroundColour( wxSystemSettings::GetColour( wxSYS_COLOUR_GRAYTEXT ) );
@@ -1862,7 +1859,7 @@ ConfigDlgGenerated::ConfigDlgGenerated( wxWindow* parent, wxWindowID id, const w
     m_panelSyncSettingsHolder->SetSizer( bSizer276 );
     m_panelSyncSettingsHolder->Layout();
     bSizer276->Fit( m_panelSyncSettingsHolder );
-    m_notebook->AddPage( m_panelSyncSettingsHolder, _("dummy"), true );
+    m_notebook->AddPage( m_panelSyncSettingsHolder, _("dummy"), false );
 
     bSizer190->Add( m_notebook, 1, wxEXPAND|wxTOP|wxRIGHT|wxLEFT, 5 );
 
@@ -1933,8 +1930,8 @@ ConfigDlgGenerated::ConfigDlgGenerated( wxWindow* parent, wxWindowID id, const w
     m_radioBtnRecycler->Connect( wxEVT_COMMAND_RADIOBUTTON_SELECTED, wxCommandEventHandler( ConfigDlgGenerated::OnDeletionRecycler ), NULL, this );
     m_radioBtnPermanent->Connect( wxEVT_COMMAND_RADIOBUTTON_SELECTED, wxCommandEventHandler( ConfigDlgGenerated::OnDeletionPermanent ), NULL, this );
     m_radioBtnVersioning->Connect( wxEVT_COMMAND_RADIOBUTTON_SELECTED, wxCommandEventHandler( ConfigDlgGenerated::OnDeletionVersioning ), NULL, this );
-    m_hyperlink17->Connect( wxEVT_COMMAND_HYPERLINK, wxHyperlinkEventHandler( ConfigDlgGenerated::OnHelpVersioning ), NULL, this );
     m_choiceVersioningStyle->Connect( wxEVT_COMMAND_CHOICE_SELECTED, wxCommandEventHandler( ConfigDlgGenerated::OnChangeSyncOption ), NULL, this );
+    m_hyperlink17->Connect( wxEVT_COMMAND_HYPERLINK, wxHyperlinkEventHandler( ConfigDlgGenerated::OnHelpVersioning ), NULL, this );
     m_radioBtnPopupOnErrors->Connect( wxEVT_COMMAND_RADIOBUTTON_SELECTED, wxCommandEventHandler( ConfigDlgGenerated::OnErrorPopup ), NULL, this );
     m_radioBtnIgnoreErrors->Connect( wxEVT_COMMAND_RADIOBUTTON_SELECTED, wxCommandEventHandler( ConfigDlgGenerated::OnErrorIgnore ), NULL, this );
     m_buttonOkay->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( ConfigDlgGenerated::OnOkay ), NULL, this );
@@ -3823,7 +3820,7 @@ OptionsDlgGenerated::~OptionsDlgGenerated()
 {
 }
 
-TooltipDialogGenerated::TooltipDialogGenerated( wxWindow* parent, wxWindowID id, const wxString& title, const wxPoint& pos, const wxSize& size, long style ) : wxDialog( parent, id, title, pos, size, style )
+TooltipDlgGenerated::TooltipDlgGenerated( wxWindow* parent, wxWindowID id, const wxString& title, const wxPoint& pos, const wxSize& size, long style ) : wxDialog( parent, id, title, pos, size, style )
 {
     this->SetSizeHints( wxDefaultSize, wxDefaultSize );
 
@@ -3843,7 +3840,7 @@ TooltipDialogGenerated::TooltipDialogGenerated( wxWindow* parent, wxWindowID id,
     bSizer158->Fit( this );
 }
 
-TooltipDialogGenerated::~TooltipDialogGenerated()
+TooltipDlgGenerated::~TooltipDlgGenerated()
 {
 }
 
@@ -4017,6 +4014,57 @@ AboutDlgGenerated::AboutDlgGenerated( wxWindow* parent, wxWindowID id, const wxS
 
     bSizer181->Add( bSizer187, 0, wxALL|wxEXPAND, 5 );
 
+    m_panelThankYou = new wxPanel( m_panel41, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL );
+    m_panelThankYou->SetBackgroundColour( wxColour( 153, 170, 187 ) );
+
+    wxBoxSizer* bSizer1831;
+    bSizer1831 = new wxBoxSizer( wxVERTICAL );
+
+    m_panel391 = new wxPanel( m_panelThankYou, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL );
+    m_panel391->SetBackgroundColour( wxColour( 224, 247, 201 ) );
+
+    wxBoxSizer* bSizer1841;
+    bSizer1841 = new wxBoxSizer( wxHORIZONTAL );
+
+
+    bSizer1841->Add( 0, 0, 1, wxEXPAND, 5 );
+
+    m_bitmapThanks = new wxStaticBitmap( m_panel391, wxID_ANY, wxNullBitmap, wxDefaultPosition, wxDefaultSize, 0 );
+    bSizer1841->Add( m_bitmapThanks, 0, wxALIGN_CENTER_VERTICAL, 5 );
+
+    wxBoxSizer* bSizer1781;
+    bSizer1781 = new wxBoxSizer( wxVERTICAL );
+
+    m_staticTextThanks = new wxStaticText( m_panel391, wxID_ANY, _("dummy"), wxDefaultPosition, wxDefaultSize, wxALIGN_CENTRE );
+    m_staticTextThanks->Wrap( -1 );
+    m_staticTextThanks->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 90, false, wxEmptyString ) );
+    m_staticTextThanks->SetForegroundColour( wxColour( 0, 0, 0 ) );
+
+    bSizer1781->Add( m_staticTextThanks, 0, wxALL|wxALIGN_CENTER_HORIZONTAL, 5 );
+
+    m_buttonShowDonationDetails = new wxButton( m_panel391, wxID_ANY, _("Donation details"), wxDefaultPosition, wxDefaultSize, 0 );
+    m_buttonShowDonationDetails->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 90, false, wxEmptyString ) );
+
+    bSizer1781->Add( m_buttonShowDonationDetails, 0, wxBOTTOM|wxRIGHT|wxLEFT|wxALIGN_CENTER_HORIZONTAL, 5 );
+
+
+    bSizer1841->Add( bSizer1781, 0, wxALIGN_CENTER_VERTICAL, 5 );
+
+
+    bSizer1841->Add( 0, 0, 1, wxEXPAND, 5 );
+
+
+    m_panel391->SetSizer( bSizer1841 );
+    m_panel391->Layout();
+    bSizer1841->Fit( m_panel391 );
+    bSizer1831->Add( m_panel391, 0, wxEXPAND|wxALL, 5 );
+
+
+    m_panelThankYou->SetSizer( bSizer1831 );
+    m_panelThankYou->Layout();
+    bSizer1831->Fit( m_panelThankYou );
+    bSizer181->Add( m_panelThankYou, 0, wxEXPAND|wxRIGHT|wxLEFT, 5 );
+
     m_panelDonate = new wxPanel( m_panel41, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL );
     m_panelDonate->SetBackgroundColour( wxColour( 153, 170, 187 ) );
 
@@ -4038,12 +4086,12 @@ AboutDlgGenerated::AboutDlgGenerated( wxWindow* parent, wxWindowID id, const wxS
     wxBoxSizer* bSizer178;
     bSizer178 = new wxBoxSizer( wxVERTICAL );
 
-    m_staticText83 = new wxStaticText( m_panel39, wxID_ANY, _("If you like FreeFileSync:"), wxDefaultPosition, wxDefaultSize, 0 );
-    m_staticText83->Wrap( -1 );
-    m_staticText83->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 92, false, wxEmptyString ) );
-    m_staticText83->SetForegroundColour( wxColour( 0, 0, 0 ) );
+    m_staticTextDonate = new wxStaticText( m_panel39, wxID_ANY, _("If you like FreeFileSync:"), wxDefaultPosition, wxDefaultSize, wxALIGN_CENTRE );
+    m_staticTextDonate->Wrap( -1 );
+    m_staticTextDonate->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 90, false, wxEmptyString ) );
+    m_staticTextDonate->SetForegroundColour( wxColour( 0, 0, 0 ) );
 
-    bSizer178->Add( m_staticText83, 0, wxALL|wxALIGN_CENTER_HORIZONTAL, 5 );
+    bSizer178->Add( m_staticTextDonate, 0, wxALL|wxALIGN_CENTER_HORIZONTAL, 5 );
 
     m_buttonDonate = new wxButton( m_panel39, wxID_ANY, _("Donate with PayPal"), wxDefaultPosition, wxDefaultSize, 0 );
     m_buttonDonate->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 90, false, wxEmptyString ) );
@@ -4083,7 +4131,7 @@ AboutDlgGenerated::AboutDlgGenerated( wxWindow* parent, wxWindowID id, const wxS
     bSizer166->Add( 0, 0, 1, wxEXPAND, 5 );
 
     m_bitmapHomepage = new wxStaticBitmap( m_panel41, wxID_ANY, wxNullBitmap, wxDefaultPosition, wxSize( -1,-1 ), 0 );
-    m_bitmapHomepage->SetToolTip( _("Homepage") );
+    m_bitmapHomepage->SetToolTip( _("Home page") );
 
     bSizer166->Add( m_bitmapHomepage, 0, wxALIGN_CENTER_VERTICAL|wxRIGHT|wxLEFT, 5 );
 
@@ -4211,6 +4259,7 @@ AboutDlgGenerated::AboutDlgGenerated( wxWindow* parent, wxWindowID id, const wxS
 
     // Connect Events
     this->Connect( wxEVT_CLOSE_WINDOW, wxCloseEventHandler( AboutDlgGenerated::OnClose ) );
+    m_buttonShowDonationDetails->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( AboutDlgGenerated::OnShowDonationDetails ), NULL, this );
     m_buttonDonate->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( AboutDlgGenerated::OnDonate ), NULL, this );
     m_buttonClose->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( AboutDlgGenerated::OnOK ), NULL, this );
 }
@@ -4218,3 +4267,244 @@ AboutDlgGenerated::AboutDlgGenerated( wxWindow* parent, wxWindowID id, const wxS
 AboutDlgGenerated::~AboutDlgGenerated()
 {
 }
+
+DownloadProgressDlgGenerated::DownloadProgressDlgGenerated( wxWindow* parent, wxWindowID id, const wxString& title, const wxPoint& pos, const wxSize& size, long style ) : wxDialog( parent, id, title, pos, size, style )
+{
+    this->SetSizeHints( wxDefaultSize, wxDefaultSize );
+
+    wxBoxSizer* bSizer24;
+    bSizer24 = new wxBoxSizer( wxVERTICAL );
+
+    wxBoxSizer* bSizer72;
+    bSizer72 = new wxBoxSizer( wxHORIZONTAL );
+
+    m_bitmapDownloading = new wxStaticBitmap( this, wxID_ANY, wxNullBitmap, wxDefaultPosition, wxDefaultSize, 0 );
+    bSizer72->Add( m_bitmapDownloading, 0, wxALIGN_CENTER_VERTICAL|wxTOP|wxBOTTOM|wxLEFT, 10 );
+
+    m_staticTextHeader = new wxStaticText( this, wxID_ANY, _("dummy"), wxDefaultPosition, wxDefaultSize, 0|wxNO_BORDER );
+    m_staticTextHeader->Wrap( 460 );
+    bSizer72->Add( m_staticTextHeader, 0, wxALIGN_CENTER_VERTICAL|wxALL, 10 );
+
+
+    bSizer72->Add( 20, 0, 0, 0, 5 );
+
+
+    bSizer24->Add( bSizer72, 0, 0, 5 );
+
+    wxBoxSizer* bSizer212;
+    bSizer212 = new wxBoxSizer( wxVERTICAL );
+
+    m_gaugeProgress = new wxGauge( this, wxID_ANY, 100, wxDefaultPosition, wxDefaultSize, wxGA_HORIZONTAL );
+    m_gaugeProgress->SetValue( 0 );
+    bSizer212->Add( m_gaugeProgress, 0, wxEXPAND|wxRIGHT|wxLEFT, 5 );
+
+    m_staticTextDetails = new wxStaticText( this, wxID_ANY, _("dummy"), wxDefaultPosition, wxDefaultSize, 0 );
+    m_staticTextDetails->Wrap( -1 );
+    bSizer212->Add( m_staticTextDetails, 0, wxALIGN_CENTER_HORIZONTAL|wxALL, 5 );
+
+
+    bSizer24->Add( bSizer212, 0, wxBOTTOM|wxRIGHT|wxLEFT, 5 );
+
+    m_staticline9 = new wxStaticLine( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL );
+    bSizer24->Add( m_staticline9, 0, wxEXPAND, 5 );
+
+    bSizerStdButtons = new wxBoxSizer( wxHORIZONTAL );
+
+    m_buttonCancel = new wxButton( this, wxID_CANCEL, _("Cancel"), wxDefaultPosition, wxSize( -1,-1 ), 0 );
+    m_buttonCancel->SetDefault();
+    bSizerStdButtons->Add( m_buttonCancel, 0, wxALIGN_CENTER_VERTICAL|wxALL, 5 );
+
+
+    bSizer24->Add( bSizerStdButtons, 0, wxALIGN_RIGHT, 5 );
+
+
+    this->SetSizer( bSizer24 );
+    this->Layout();
+    bSizer24->Fit( this );
+
+    // Connect Events
+    m_buttonCancel->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( DownloadProgressDlgGenerated::OnCancel ), NULL, this );
+}
+
+DownloadProgressDlgGenerated::~DownloadProgressDlgGenerated()
+{
+}
+
+ActivationDlgGenerated::ActivationDlgGenerated( wxWindow* parent, wxWindowID id, const wxString& title, const wxPoint& pos, const wxSize& size, long style ) : wxDialog( parent, id, title, pos, size, style )
+{
+    this->SetSizeHints( wxSize( -1,-1 ), wxDefaultSize );
+    this->SetBackgroundColour( wxSystemSettings::GetColour( wxSYS_COLOUR_BTNFACE ) );
+
+    wxBoxSizer* bSizer54;
+    bSizer54 = new wxBoxSizer( wxVERTICAL );
+
+    m_panel35 = new wxPanel( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL );
+    m_panel35->SetBackgroundColour( wxSystemSettings::GetColour( wxSYS_COLOUR_WINDOW ) );
+
+    wxBoxSizer* bSizer172;
+    bSizer172 = new wxBoxSizer( wxVERTICAL );
+
+    wxBoxSizer* bSizer165;
+    bSizer165 = new wxBoxSizer( wxHORIZONTAL );
+
+    m_bitmapActivation = new wxStaticBitmap( m_panel35, wxID_ANY, wxNullBitmap, wxDefaultPosition, wxSize( -1,-1 ), 0 );
+    bSizer165->Add( m_bitmapActivation, 0, wxALL, 10 );
+
+
+    bSizer165->Add( 0, 120, 0, 0, 5 );
+
+    wxBoxSizer* bSizer16;
+    bSizer16 = new wxBoxSizer( wxVERTICAL );
+
+
+    bSizer16->Add( 0, 10, 0, 0, 5 );
+
+    m_textCtrlLastError = new wxTextCtrl( m_panel35, wxID_ANY, wxEmptyString, wxDefaultPosition, wxDefaultSize, wxTE_MULTILINE|wxTE_READONLY|wxNO_BORDER );
+    bSizer16->Add( m_textCtrlLastError, 1, wxEXPAND, 5 );
+
+
+    bSizer16->Add( 0, 5, 0, 0, 5 );
+
+
+    bSizer165->Add( bSizer16, 1, wxEXPAND, 5 );
+
+
+    bSizer172->Add( bSizer165, 1, wxEXPAND, 5 );
+
+    m_staticTextMain = new wxStaticText( m_panel35, wxID_ANY, _("Activate the FreeFileSync Donation Edition by one of the following methods:"), wxDefaultPosition, wxDefaultSize, 0 );
+    m_staticTextMain->Wrap( -1 );
+    bSizer172->Add( m_staticTextMain, 0, wxBOTTOM|wxRIGHT|wxLEFT, 10 );
+
+
+    m_panel35->SetSizer( bSizer172 );
+    m_panel35->Layout();
+    bSizer172->Fit( m_panel35 );
+    bSizer54->Add( m_panel35, 1, wxEXPAND, 5 );
+
+    m_staticline181 = new wxStaticLine( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL );
+    bSizer54->Add( m_staticline181, 0, wxEXPAND|wxBOTTOM, 5 );
+
+    m_staticline18111 = new wxStaticLine( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL );
+    bSizer54->Add( m_staticline18111, 0, wxEXPAND|wxTOP, 5 );
+
+    m_panel3511 = new wxPanel( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL );
+    m_panel3511->SetBackgroundColour( wxSystemSettings::GetColour( wxSYS_COLOUR_WINDOW ) );
+
+    wxBoxSizer* bSizer263;
+    bSizer263 = new wxBoxSizer( wxVERTICAL );
+
+    wxBoxSizer* bSizer234;
+    bSizer234 = new wxBoxSizer( wxHORIZONTAL );
+
+    m_staticText136 = new wxStaticText( m_panel3511, wxID_ANY, _("1. Activate via internet now:"), wxDefaultPosition, wxDefaultSize, 0 );
+    m_staticText136->Wrap( -1 );
+    bSizer234->Add( m_staticText136, 1, wxALIGN_CENTER_VERTICAL|wxTOP|wxBOTTOM|wxLEFT, 5 );
+
+    m_buttonActivateOnline = new wxButton( m_panel3511, wxID_ANY, _("Activate online"), wxDefaultPosition, wxSize( -1,-1 ), 0 );
+    m_buttonActivateOnline->SetDefault();
+    m_buttonActivateOnline->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 92, false, wxEmptyString ) );
+
+    bSizer234->Add( m_buttonActivateOnline, 0, wxALIGN_CENTER_VERTICAL|wxALL, 5 );
+
+
+    bSizer263->Add( bSizer234, 0, wxEXPAND|wxALL, 5 );
+
+
+    m_panel3511->SetSizer( bSizer263 );
+    m_panel3511->Layout();
+    bSizer263->Fit( m_panel3511 );
+    bSizer54->Add( m_panel3511, 0, wxEXPAND, 5 );
+
+    m_staticline181111 = new wxStaticLine( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL );
+    bSizer54->Add( m_staticline181111, 0, wxEXPAND|wxBOTTOM, 5 );
+
+    m_staticline181112 = new wxStaticLine( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL );
+    bSizer54->Add( m_staticline181112, 0, wxEXPAND|wxTOP, 5 );
+
+    m_panel351 = new wxPanel( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL );
+    m_panel351->SetBackgroundColour( wxSystemSettings::GetColour( wxSYS_COLOUR_WINDOW ) );
+
+    wxBoxSizer* bSizer266;
+    bSizer266 = new wxBoxSizer( wxVERTICAL );
+
+    wxBoxSizer* bSizer237;
+    bSizer237 = new wxBoxSizer( wxVERTICAL );
+
+    wxBoxSizer* bSizer236;
+    bSizer236 = new wxBoxSizer( wxHORIZONTAL );
+
+    m_staticText1361 = new wxStaticText( m_panel351, wxID_ANY, _("2. Retrieve an offline activation key from the following URL:"), wxDefaultPosition, wxDefaultSize, 0 );
+    m_staticText1361->Wrap( -1 );
+    bSizer236->Add( m_staticText1361, 1, wxALIGN_CENTER_VERTICAL|wxTOP|wxBOTTOM|wxLEFT, 5 );
+
+    m_buttonCopyUrl = new wxButton( m_panel351, wxID_ANY, _("&Copy to clipboard"), wxDefaultPosition, wxSize( -1,-1 ), 0 );
+    m_buttonCopyUrl->SetDefault();
+    m_buttonCopyUrl->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 90, false, wxEmptyString ) );
+
+    bSizer236->Add( m_buttonCopyUrl, 0, wxALIGN_CENTER_VERTICAL|wxALL, 5 );
+
+
+    bSizer237->Add( bSizer236, 0, wxEXPAND, 5 );
+
+    m_textCtrlManualActivationUrl = new wxTextCtrl( m_panel351, wxID_ANY, wxEmptyString, wxDefaultPosition, wxSize( 220,-1 ), wxTE_MULTILINE|wxTE_READONLY|wxWANTS_CHARS );
+    m_textCtrlManualActivationUrl->SetMaxLength( 0 );
+    bSizer237->Add( m_textCtrlManualActivationUrl, 0, wxEXPAND|wxBOTTOM|wxRIGHT|wxLEFT, 5 );
+
+    wxBoxSizer* bSizer235;
+    bSizer235 = new wxBoxSizer( wxHORIZONTAL );
+
+    m_staticText13611 = new wxStaticText( m_panel351, wxID_ANY, _("Enter activation key:"), wxDefaultPosition, wxDefaultSize, 0 );
+    m_staticText13611->Wrap( -1 );
+    bSizer235->Add( m_staticText13611, 0, wxALIGN_CENTER_VERTICAL|wxTOP|wxBOTTOM|wxLEFT, 5 );
+
+    m_textCtrlOfflineActivationKey = new wxTextCtrl( m_panel351, wxID_ANY, wxEmptyString, wxDefaultPosition, wxSize( 220,-1 ), wxTE_PROCESS_ENTER|wxWANTS_CHARS );
+    m_textCtrlOfflineActivationKey->SetMaxLength( 0 );
+    bSizer235->Add( m_textCtrlOfflineActivationKey, 1, wxTOP|wxBOTTOM|wxLEFT|wxALIGN_CENTER_VERTICAL, 5 );
+
+    m_buttonActivateOffline = new wxButton( m_panel351, wxID_ANY, _("Activate offline"), wxDefaultPosition, wxSize( -1,-1 ), 0 );
+    m_buttonActivateOffline->SetFont( wxFont( wxNORMAL_FONT->GetPointSize(), 70, 90, 92, false, wxEmptyString ) );
+
+    bSizer235->Add( m_buttonActivateOffline, 0, wxALL|wxALIGN_CENTER_VERTICAL, 5 );
+
+
+    bSizer237->Add( bSizer235, 0, wxEXPAND, 5 );
+
+
+    bSizer266->Add( bSizer237, 0, wxALL|wxEXPAND, 5 );
+
+
+    m_panel351->SetSizer( bSizer266 );
+    m_panel351->Layout();
+    bSizer266->Fit( m_panel351 );
+    bSizer54->Add( m_panel351, 0, wxEXPAND, 5 );
+
+    m_staticline13 = new wxStaticLine( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL );
+    bSizer54->Add( m_staticline13, 0, wxEXPAND, 5 );
+
+    bSizerStdButtons = new wxBoxSizer( wxHORIZONTAL );
+
+    m_buttonCancel = new wxButton( this, wxID_CANCEL, _("Cancel"), wxDefaultPosition, wxSize( -1,-1 ), 0 );
+    bSizerStdButtons->Add( m_buttonCancel, 0, wxALIGN_CENTER_VERTICAL|wxTOP|wxBOTTOM|wxRIGHT, 5 );
+
+
+    bSizer54->Add( bSizerStdButtons, 0, wxALIGN_RIGHT, 5 );
+
+
+    this->SetSizer( bSizer54 );
+    this->Layout();
+    bSizer54->Fit( this );
+
+    this->Centre( wxBOTH );
+
+    // Connect Events
+    this->Connect( wxEVT_CLOSE_WINDOW, wxCloseEventHandler( ActivationDlgGenerated::OnClose ) );
+    m_buttonActivateOnline->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( ActivationDlgGenerated::OnActivateOnline ), NULL, this );
+    m_buttonCopyUrl->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( ActivationDlgGenerated::OnCopyUrl ), NULL, this );
+    m_textCtrlOfflineActivationKey->Connect( wxEVT_COMMAND_TEXT_ENTER, wxCommandEventHandler( ActivationDlgGenerated::OnOfflineActivationEnter ), NULL, this );
+    m_buttonActivateOffline->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( ActivationDlgGenerated::OnActivateOffline ), NULL, this );
+    m_buttonCancel->Connect( wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler( ActivationDlgGenerated::OnCancel ), NULL, this );
+}
+
+ActivationDlgGenerated::~ActivationDlgGenerated()
+{
+}
diff --git a/FreeFileSync/Source/ui/gui_generated.h b/FreeFileSync/Source/ui/gui_generated.h
index 9ab016bf..ac691409 100644
--- a/FreeFileSync/Source/ui/gui_generated.h
+++ b/FreeFileSync/Source/ui/gui_generated.h
@@ -52,6 +52,7 @@ namespace zen { class TripleSplitter; }
 #include <wx/animate.h>
 #include <wx/grid.h>
 #include <wx/calctrl.h>
+#include <wx/gauge.h>
 
 #include "zen/i18n.h"
 
@@ -82,9 +83,9 @@ protected:
     wxMenu* m_menuTools;
     wxMenuItem* m_menuItemOptions;
     wxMenu* m_menuLanguages;
+    wxMenuItem* m_menuItemFind;
     wxMenu* m_menuHelp;
     wxMenuItem* m_menuItemHelp;
-    wxMenu* m_menuCheckVersion;
     wxMenuItem* m_menuItemCheckVersionNow;
     wxMenuItem* m_menuItemCheckVersionAuto;
     wxMenuItem* m_menuItemAbout;
@@ -373,9 +374,9 @@ protected:
     FolderHistoryBox* m_versioningFolderPath;
     wxButton* m_buttonSelectVersioningFolder;
     wxStaticText* m_staticText93;
+    wxChoice* m_choiceVersioningStyle;
     wxHyperlinkCtrl* m_hyperlink17;
     wxBoxSizer* bSizer192;
-    wxChoice* m_choiceVersioningStyle;
     wxStaticText* m_staticTextNamingCvtPart1;
     wxStaticText* m_staticTextNamingCvtPart2Bold;
     wxStaticText* m_staticTextNamingCvtPart3;
@@ -431,8 +432,8 @@ protected:
     virtual void OnDeletionRecycler( wxCommandEvent& event ) { event.Skip(); }
     virtual void OnDeletionPermanent( wxCommandEvent& event ) { event.Skip(); }
     virtual void OnDeletionVersioning( wxCommandEvent& event ) { event.Skip(); }
-    virtual void OnHelpVersioning( wxHyperlinkEvent& event ) { event.Skip(); }
     virtual void OnChangeSyncOption( wxCommandEvent& event ) { event.Skip(); }
+    virtual void OnHelpVersioning( wxHyperlinkEvent& event ) { event.Skip(); }
     virtual void OnErrorPopup( wxCommandEvent& event ) { event.Skip(); }
     virtual void OnErrorIgnore( wxCommandEvent& event ) { event.Skip(); }
     virtual void OnOkay( wxCommandEvent& event ) { event.Skip(); }
@@ -928,9 +929,9 @@ public:
 };
 
 ///////////////////////////////////////////////////////////////////////////////
-/// Class TooltipDialogGenerated
+/// Class TooltipDlgGenerated
 ///////////////////////////////////////////////////////////////////////////////
-class TooltipDialogGenerated : public wxDialog
+class TooltipDlgGenerated : public wxDialog
 {
 private:
 
@@ -940,8 +941,8 @@ public:
     wxStaticBitmap* m_bitmapLeft;
     wxStaticText* m_staticTextMain;
 
-    TooltipDialogGenerated( wxWindow* parent, wxWindowID id = wxID_ANY, const wxString& title = wxEmptyString, const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize, long style = wxDEFAULT_DIALOG_STYLE );
-    ~TooltipDialogGenerated();
+    TooltipDlgGenerated( wxWindow* parent, wxWindowID id = wxID_ANY, const wxString& title = wxEmptyString, const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize, long style = wxDEFAULT_DIALOG_STYLE );
+    ~TooltipDlgGenerated();
 
 };
 
@@ -998,10 +999,15 @@ protected:
     wxHyperlinkCtrl* m_hyperlink10;
     wxHyperlinkCtrl* m_hyperlink18;
     wxHyperlinkCtrl* m_hyperlink9;
+    wxPanel* m_panelThankYou;
+    wxPanel* m_panel391;
+    wxStaticBitmap* m_bitmapThanks;
+    wxStaticText* m_staticTextThanks;
+    wxButton* m_buttonShowDonationDetails;
     wxPanel* m_panelDonate;
     wxPanel* m_panel39;
     wxStaticBitmap* m_bitmapDonate;
-    wxStaticText* m_staticText83;
+    wxStaticText* m_staticTextDonate;
     wxButton* m_buttonDonate;
     wxStaticText* m_staticText94;
     wxStaticBitmap* m_bitmapHomepage;
@@ -1022,6 +1028,7 @@ protected:
 
     // Virtual event handlers, overide them in your derived class
     virtual void OnClose( wxCloseEvent& event ) { event.Skip(); }
+    virtual void OnShowDonationDetails( wxCommandEvent& event ) { event.Skip(); }
     virtual void OnDonate( wxCommandEvent& event ) { event.Skip(); }
     virtual void OnOK( wxCommandEvent& event ) { event.Skip(); }
 
@@ -1033,4 +1040,77 @@ public:
 
 };
 
+///////////////////////////////////////////////////////////////////////////////
+/// Class DownloadProgressDlgGenerated
+///////////////////////////////////////////////////////////////////////////////
+class DownloadProgressDlgGenerated : public wxDialog
+{
+private:
+
+protected:
+    wxStaticBitmap* m_bitmapDownloading;
+    wxStaticText* m_staticTextHeader;
+    wxGauge* m_gaugeProgress;
+    wxStaticText* m_staticTextDetails;
+    wxStaticLine* m_staticline9;
+    wxBoxSizer* bSizerStdButtons;
+    wxButton* m_buttonCancel;
+
+    // Virtual event handlers, overide them in your derived class
+    virtual void OnCancel( wxCommandEvent& event ) { event.Skip(); }
+
+
+public:
+
+    DownloadProgressDlgGenerated( wxWindow* parent, wxWindowID id = wxID_ANY, const wxString& title = wxEmptyString, const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize, long style = 0 );
+    ~DownloadProgressDlgGenerated();
+
+};
+
+///////////////////////////////////////////////////////////////////////////////
+/// Class ActivationDlgGenerated
+///////////////////////////////////////////////////////////////////////////////
+class ActivationDlgGenerated : public wxDialog
+{
+private:
+
+protected:
+    wxPanel* m_panel35;
+    wxStaticBitmap* m_bitmapActivation;
+    wxTextCtrl* m_textCtrlLastError;
+    wxStaticText* m_staticTextMain;
+    wxStaticLine* m_staticline181;
+    wxStaticLine* m_staticline18111;
+    wxPanel* m_panel3511;
+    wxStaticText* m_staticText136;
+    wxButton* m_buttonActivateOnline;
+    wxStaticLine* m_staticline181111;
+    wxStaticLine* m_staticline181112;
+    wxPanel* m_panel351;
+    wxStaticText* m_staticText1361;
+    wxButton* m_buttonCopyUrl;
+    wxTextCtrl* m_textCtrlManualActivationUrl;
+    wxStaticText* m_staticText13611;
+    wxTextCtrl* m_textCtrlOfflineActivationKey;
+    wxButton* m_buttonActivateOffline;
+    wxStaticLine* m_staticline13;
+    wxBoxSizer* bSizerStdButtons;
+    wxButton* m_buttonCancel;
+
+    // Virtual event handlers, overide them in your derived class
+    virtual void OnClose( wxCloseEvent& event ) { event.Skip(); }
+    virtual void OnActivateOnline( wxCommandEvent& event ) { event.Skip(); }
+    virtual void OnCopyUrl( wxCommandEvent& event ) { event.Skip(); }
+    virtual void OnOfflineActivationEnter( wxCommandEvent& event ) { event.Skip(); }
+    virtual void OnActivateOffline( wxCommandEvent& event ) { event.Skip(); }
+    virtual void OnCancel( wxCommandEvent& event ) { event.Skip(); }
+
+
+public:
+
+    ActivationDlgGenerated( wxWindow* parent, wxWindowID id = wxID_ANY, const wxString& title = _("FreeFileSync Donation Edition"), const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize, long style = wxDEFAULT_DIALOG_STYLE|wxRESIZE_BORDER );
+    ~ActivationDlgGenerated();
+
+};
+
 #endif //__GUI_GENERATED_H__
diff --git a/FreeFileSync/Source/ui/gui_status_handler.cpp b/FreeFileSync/Source/ui/gui_status_handler.cpp
index b7427321..be40b2bf 100644
--- a/FreeFileSync/Source/ui/gui_status_handler.cpp
+++ b/FreeFileSync/Source/ui/gui_status_handler.cpp
@@ -362,7 +362,7 @@ StatusHandlerFloatingDialog::~StatusHandlerFloatingDialog()
         while (progressDlg)
         {
             wxTheApp->Yield(); //*first* refresh GUI (removing flicker) before sleeping!
-            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL));
+            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS));
         }
     }
 }
@@ -403,12 +403,12 @@ ProcessCallback::Response StatusHandlerFloatingDialog::reportError(const std::ws
         errorLog_.logMsg(errorMessage + L"\n-> " +
                          _P("Automatic retry in 1 second...", "Automatic retry in %x seconds...", automaticRetryDelay_), TYPE_INFO);
         //delay
-        const int iterations = static_cast<int>(1000 * automaticRetryDelay_ / UI_UPDATE_INTERVAL); //always round down: don't allow for negative remaining time below
+        const int iterations = static_cast<int>(1000 * automaticRetryDelay_ / UI_UPDATE_INTERVAL_MS); //always round down: don't allow for negative remaining time below
         for (int i = 0; i < iterations; ++i)
         {
             reportStatus(_("Error") + L": " + _P("Automatic retry in 1 second...", "Automatic retry in %x seconds...",
-                                                 (1000 * automaticRetryDelay_ - i * UI_UPDATE_INTERVAL + 999) / 1000)); //integer round up
-            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL));
+                                                 (1000 * automaticRetryDelay_ - i * UI_UPDATE_INTERVAL_MS + 999) / 1000)); //integer round up
+            std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS));
         }
         return ProcessCallback::RETRY;
     }
diff --git a/FreeFileSync/Source/ui/main_dlg.cpp b/FreeFileSync/Source/ui/main_dlg.cpp
index a4aaf819..4d56a4f7 100644
--- a/FreeFileSync/Source/ui/main_dlg.cpp
+++ b/FreeFileSync/Source/ui/main_dlg.cpp
@@ -346,7 +346,7 @@ xmlAccess::XmlGlobalSettings loadGlobalConfig(const Zstring& globalConfigFile) /
 
 Zstring MainDialog::getLastRunConfigPath()
 {
-    return zen::getConfigDir() + Zstr("LastRun.ffs_gui");
+    return zen::getConfigDirPathPf() + Zstr("LastRun.ffs_gui");
 }
 
 
@@ -463,9 +463,7 @@ MainDialog::MainDialog(const Zstring& globalConfigFile,
                        bool startComparison) :
     MainDialogGenerated(nullptr),
     globalConfigFile_(globalConfigFile),
-    lastRunConfigPath(getLastRunConfigPath()),
-    folderHistoryLeft (std::make_shared<FolderHistory>()), //make sure it is always bound
-    folderHistoryRight(std::make_shared<FolderHistory>())  //
+    lastRunConfigPath(getLastRunConfigPath())
 {
     m_folderPathLeft ->init(folderHistoryLeft);
     m_folderPathRight->init(folderHistoryRight);
@@ -652,21 +650,11 @@ MainDialog::MainDialog(const Zstring& globalConfigFile,
     m_menuItemSynchronize ->SetBitmap(getResourceImage(L"sync_small"));
 
     m_menuItemOptions     ->SetBitmap(getResourceImage(L"settings_small"));
+    m_menuItemFind        ->SetBitmap(getResourceImage(L"find_small"));
 
     m_menuItemHelp ->SetBitmap(getResourceImage(L"help_small"));
     m_menuItemAbout->SetBitmap(getResourceImage(L"about_small"));
-
-    if (!manualProgramUpdateRequired())
-    {
-        m_menuItemCheckVersionNow ->Enable(false);
-        m_menuItemCheckVersionAuto->Enable(false);
-
-        //wxFormbuilder doesn't give us a wxMenuItem for m_menuCheckVersion, so we need this abomination:
-        wxMenuItemList& items = m_menuHelp->GetMenuItems();
-        for (auto it = items.begin(); it != items.end(); ++it)
-            if ((*it)->GetSubMenu() == m_menuCheckVersion)
-                (*it)->Enable(false);
-    }
+    m_menuItemCheckVersionNow->SetBitmap(getResourceImage(L"update_check_small"));
 
     //create language selection menu
     for (const TranslationInfo& ti : getExistingTranslations())
@@ -686,8 +674,8 @@ MainDialog::MainDialog(const Zstring& globalConfigFile,
     if (!globalSettings.gui.lastOnlineVersion.empty() && haveNewerVersionOnline(globalSettings.gui.lastOnlineVersion))
     {
         auto menu = new wxMenu();
-        wxMenuItem* newItem = new wxMenuItem(menu, wxID_ANY, _("&Download"));
-        this->Connect(newItem->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler(MainDialog::OnMenuDownloadNewVersion));
+        wxMenuItem* newItem = new wxMenuItem(menu, wxID_ANY, _("&Show details"));
+        this->Connect(newItem->GetId(), wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler(MainDialog::OnMenuUpdateAvailable));
         menu->Append(newItem); //pass ownership
         m_menubar1->Append(menu, L"\u21D2 " + _("A new version of FreeFileSync is available:") + L" \u2605 " + globalSettings.gui.lastOnlineVersion + L" \u2605");
     }
@@ -1619,7 +1607,7 @@ void MainDialog::flashStatusInformation(const wxString& text)
     oldStatusMsgs.push_back(m_staticTextStatusCenter->GetLabel());
 
     m_staticTextStatusCenter->SetLabel(text);
-    m_staticTextStatusCenter->SetForegroundColour(wxColor(31, 57, 226)); //highlight color: blue
+    m_staticTextStatusCenter->SetForegroundColour(wxColor(31, 57, 226)); //highlight_ color: blue
     m_staticTextStatusCenter->SetFont(m_staticTextStatusCenter->GetFont().Bold());
 
     m_panelStatusBar->Layout();
@@ -2494,18 +2482,32 @@ void MainDialog::onGridLabelContextRim(Grid& grid, ColumnTypeRim type, bool left
     {
         auto colAttr = grid.getColumnConfig();
 
+        Grid::ColumnAttribute* caItemPath = nullptr;
+        Grid::ColumnAttribute* caToggle   = nullptr;
+
         for (Grid::ColumnAttribute& ca : colAttr)
-            if (ca.type_ == ct)
-            {
-                ca.visible_ = !ca.visible_;
-                grid.setColumnConfig(colAttr);
-                return;
-            }
+            if (ca.type_ == static_cast<ColumnType>(ColumnTypeRim::ITEM_PATH))
+                caItemPath = &ca;
+            else if (ca.type_ == ct)
+                caToggle = &ca;
+
+        assert(caItemPath && caItemPath->stretch_ > 0 && caItemPath->visible_);
+        assert(caToggle   && caToggle->stretch_ == 0);
+
+        if (caItemPath && caToggle)
+        {
+            caToggle->visible_ = !caToggle->visible_;
+
+            //take width of newly visible column from stretched item path column
+            caItemPath->offset_ -= caToggle->visible_ ? caToggle->offset_ : -caToggle->offset_;
+
+            grid.setColumnConfig(colAttr);
+        }
     };
 
     if (const GridData* prov = grid.getDataProvider())
         for (const Grid::ColumnAttribute& ca : grid.getColumnConfig())
-            menu.addCheckBox(prov->getColumnLabel(ca.type_), [ca, toggleColumn] { toggleColumn(ca.type_); },
+            menu.addCheckBox(prov->getColumnLabel(ca.type_), [ct = ca.type_, toggleColumn] { toggleColumn(ct); },
                              ca.visible_, ca.type_ != static_cast<ColumnType>(ColumnTypeRim::ITEM_PATH)); //do not allow user to hide this column!
     //----------------------------------------------------------------------------------------------
     menu.addSeparator();
@@ -3785,7 +3787,7 @@ void MainDialog::OnCompare(wxCommandEvent& event)
     //play (optional) sound notification
     if (!globalCfg.soundFileCompareFinished.empty())
     {
-        const Zstring soundFile = getResourceDir() + globalCfg.soundFileCompareFinished;
+        const Zstring soundFile = getResourceDirPf() + globalCfg.soundFileCompareFinished;
         if (fileExists(soundFile))
             wxSound::Play(utfCvrtTo<wxString>(soundFile), wxSOUND_ASYNC); //warning: this may fail and show a wxWidgets error message! => must not play when running FFS as batch!
     }
@@ -4890,13 +4892,13 @@ void MainDialog::OnMenuExportFileList(wxCommandEvent& event)
 
 void MainDialog::OnMenuCheckVersion(wxCommandEvent& event)
 {
-    zen::checkForUpdateNow(this, globalCfg.gui.lastOnlineVersion, globalCfg.gui.lastOnlineChangeLog);
+    zen::checkForUpdateNow(this, globalCfg.gui.lastOnlineVersion);
 }
 
 
-void MainDialog::OnMenuDownloadNewVersion(wxCommandEvent& event)
+void MainDialog::OnMenuUpdateAvailable(wxCommandEvent& event)
 {
-    wxLaunchDefaultBrowser(L"http://www.freefilesync.org/get_latest.php");
+    zen::checkForUpdateNow(this, globalCfg.gui.lastOnlineVersion); //show changelog + handle Donation Edition auto-updater (including expiration)
 }
 
 
@@ -4913,9 +4915,8 @@ void MainDialog::OnMenuCheckVersionAutomatically(wxCommandEvent& event)
     {
         flashStatusInformation(_("Searching for program updates..."));
         //synchronous update check is sufficient here:
-        periodicUpdateCheckEval(this, globalCfg.gui.lastUpdateCheck,
-                                globalCfg.gui.lastOnlineVersion,
-                                globalCfg.gui.lastOnlineChangeLog, periodicUpdateCheckRunAsync(periodicUpdateCheckPrepare().get()).get());
+        periodicUpdateCheckEval(this, globalCfg.gui.lastUpdateCheck, globalCfg.gui.lastOnlineVersion,
+                                periodicUpdateCheckRunAsync(periodicUpdateCheckPrepare().get()).get());
     }
 }
 
@@ -4925,21 +4926,19 @@ void MainDialog::OnRegularUpdateCheck(wxIdleEvent& event)
     //execute just once per startup!
     Disconnect(wxEVT_IDLE, wxIdleEventHandler(MainDialog::OnRegularUpdateCheck), nullptr, this);
 
-    if (manualProgramUpdateRequired())
-        if (shouldRunPeriodicUpdateCheck(globalCfg.gui.lastUpdateCheck))
-        {
-            flashStatusInformation(_("Searching for program updates..."));
+    if (shouldRunPeriodicUpdateCheck(globalCfg.gui.lastUpdateCheck))
+    {
+        flashStatusInformation(_("Searching for program updates..."));
 
-            std::shared_ptr<UpdateCheckResultPrep> resultPrep = periodicUpdateCheckPrepare(); //run on main thread:
+        std::shared_ptr<UpdateCheckResultPrep> resultPrep = periodicUpdateCheckPrepare(); //run on main thread:
 
-            guiQueue.processAsync([resultPrep] { return periodicUpdateCheckRunAsync(resultPrep.get()); }, //run on worker thread: (long-running part of the check)
-                                  [this] (std::shared_ptr<UpdateCheckResult>&& resultAsync)
-            {
-                periodicUpdateCheckEval(this, globalCfg.gui.lastUpdateCheck,
-                                        globalCfg.gui.lastOnlineVersion,
-                                        globalCfg.gui.lastOnlineChangeLog, resultAsync.get()); //run on main thread:
-            });
-        }
+        guiQueue.processAsync([resultPrep] { return periodicUpdateCheckRunAsync(resultPrep.get()); }, //run on worker thread: (long-running part of the check)
+                              [this] (std::shared_ptr<UpdateCheckResult>&& resultAsync)
+        {
+            periodicUpdateCheckEval(this, globalCfg.gui.lastUpdateCheck, globalCfg.gui.lastOnlineVersion,
+                                    resultAsync.get()); //run on main thread:
+        });
+    }
 }
 
 
diff --git a/FreeFileSync/Source/ui/main_dlg.h b/FreeFileSync/Source/ui/main_dlg.h
index 1bd621c2..0aace163 100644
--- a/FreeFileSync/Source/ui/main_dlg.h
+++ b/FreeFileSync/Source/ui/main_dlg.h
@@ -257,16 +257,16 @@ private:
     void OnSearchPanelKeyPressed(wxKeyEvent& event);
 
     //menu events
-    void OnMenuOptions       (wxCommandEvent& event) override;
-    void OnMenuExportFileList(wxCommandEvent& event) override;
-    void OnMenuResetLayout   (wxCommandEvent& event) override { resetLayout(); }
-    void OnMenuFindItem      (wxCommandEvent& event) override;
-    void OnMenuCheckVersion  (wxCommandEvent& event) override;
+    void OnMenuOptions        (wxCommandEvent& event) override;
+    void OnMenuExportFileList (wxCommandEvent& event) override;
+    void OnMenuResetLayout    (wxCommandEvent& event) override { resetLayout(); }
+    void OnMenuFindItem       (wxCommandEvent& event) override;
+    void OnMenuCheckVersion   (wxCommandEvent& event) override;
     void OnMenuCheckVersionAutomatically(wxCommandEvent& event) override;
-    void OnMenuDownloadNewVersion       (wxCommandEvent& event);
-    void OnMenuAbout         (wxCommandEvent& event) override;
-    void OnShowHelp          (wxCommandEvent& event) override;
-    void OnMenuQuit          (wxCommandEvent& event) override { Close(); }
+    void OnMenuUpdateAvailable(wxCommandEvent& event);
+    void OnMenuAbout          (wxCommandEvent& event) override;
+    void OnShowHelp           (wxCommandEvent& event) override;
+    void OnMenuQuit           (wxCommandEvent& event) override { Close(); }
 
     void OnMenuLanguageSwitch(wxCommandEvent& event);
 
@@ -329,8 +329,8 @@ private:
     std::int64_t manualTimeSpanFrom = 0;
     std::int64_t manualTimeSpanTo   = 0; //buffer manual time span selection at session level
 
-    std::shared_ptr<FolderHistory> folderHistoryLeft;  //shared by all wxComboBox dropdown controls
-    std::shared_ptr<FolderHistory> folderHistoryRight; //always bound!
+    std::shared_ptr<FolderHistory> folderHistoryLeft  = std::make_shared<FolderHistory>();  //shared by all wxComboBox dropdown controls
+    std::shared_ptr<FolderHistory> folderHistoryRight = std::make_shared<FolderHistory>(); //always bound!
 
     zen::AsyncGuiQueue guiQueue; //schedule and run long-running tasks asynchronously, but process results on GUI queue
 
diff --git a/FreeFileSync/Source/ui/on_completion_box.cpp b/FreeFileSync/Source/ui/on_completion_box.cpp
index 898178dc..c38909a3 100644
--- a/FreeFileSync/Source/ui/on_completion_box.cpp
+++ b/FreeFileSync/Source/ui/on_completion_box.cpp
@@ -10,9 +10,9 @@
 #include <algorithm>
 #include <zen/stl_tools.h>
 #include <zen/utf.h>
-#ifdef ZEN_WIN
-    #include <zen/win_ver.h>
-#endif
+//#ifdef ZEN_WIN
+//    #include <zen/win_ver.h>
+//#endif
 
 using namespace zen;
 
@@ -31,19 +31,16 @@ std::vector<std::pair<std::wstring, Zstring>> getDefaultCommands() //(gui name/c
     auto addEntry = [&](const std::wstring& name, const Zstring& value) { output.emplace_back(name, value); };
 
 #ifdef ZEN_WIN
-    if (zen::vistaOrLater())
-    {
-        addEntry(_("Log off"  ), Zstr("shutdown /l"));
-        addEntry(_("Standby"  ), Zstr("rundll32.exe powrprof.dll,SetSuspendState Sleep")); //suspend/Suspend to RAM/sleep
-        addEntry(_("Shut down"), Zstr("shutdown /s /t 60"));
-    }
-    else //XP
-    {
-        addEntry(_("Log off"  ), Zstr("shutdown -l"));
-        addEntry(_("Standby"  ), Zstr("rundll32.exe powrprof.dll,SetSuspendState")); //this triggers standby OR hibernate, depending on whether hibernate setting is active!
-        addEntry(_("Shut down"), Zstr("shutdown -s -t 60"));
-        //no suspend on XP?
-    }
+#ifdef ZEN_WIN_VISTA_AND_LATER
+    addEntry(_("Log off"  ), Zstr("shutdown /l"));
+    addEntry(_("Standby"  ), Zstr("rundll32.exe powrprof.dll,SetSuspendState Sleep")); //suspend/Suspend to RAM/sleep
+    addEntry(_("Shut down"), Zstr("shutdown /s /t 60"));
+#else //XP
+    addEntry(_("Log off"  ), Zstr("shutdown -l"));
+    addEntry(_("Standby"  ), Zstr("rundll32.exe powrprof.dll,SetSuspendState")); //this triggers standby OR hibernate, depending on whether hibernate setting is active!
+    addEntry(_("Shut down"), Zstr("shutdown -s -t 60"));
+    //no suspend on XP?
+#endif
 
 #elif defined ZEN_LINUX
     addEntry(_("Log off"  ), Zstr("gnome-session-quit --no-prompt")); //alternative requiring admin: sudo killall Xorg
diff --git a/FreeFileSync/Source/ui/progress_indicator.cpp b/FreeFileSync/Source/ui/progress_indicator.cpp
index c5cc1f82..93e721ea 100644
--- a/FreeFileSync/Source/ui/progress_indicator.cpp
+++ b/FreeFileSync/Source/ui/progress_indicator.cpp
@@ -68,6 +68,7 @@ inline wxColor getColorItemsBackgroundRim() { return {  53,  25, 255 }; } //dark
 
 
 //don't use wxStopWatch for long-running measurements: internally it uses ::QueryPerformanceCounter() which can overflow after only a few days:
+// std::chrono::system_clock is not a steady clock, but at least doesn't overflow!
 //http://www.freefilesync.org/forum/viewtopic.php?t=1426
 
 class StopWatch
@@ -75,41 +76,42 @@ class StopWatch
 public:
     void pause()
     {
-        if (!paused)
+        if (!paused_)
         {
-            paused = true;
-            elapsedUntilPause += numeric::dist(startTime, wxGetUTCTimeMillis().GetValue());
+            paused_ = true;
+            elapsedUntilPause_ += std::chrono::system_clock::now() - startTime_;
         }
     }
 
     void resume()
     {
-        if (paused)
+        if (paused_)
         {
-            paused = false;
-            startTime = wxGetUTCTimeMillis().GetValue();
+            paused_ = false;
+            startTime_ = std::chrono::system_clock::now();
         }
     }
 
     void restart()
     {
-        startTime = wxGetUTCTimeMillis().GetValue(); //uses ::GetSystemTimeAsFileTime()
-        paused = false;
-        elapsedUntilPause = 0;
+        paused_ = false;
+        startTime_ = std::chrono::system_clock::now();
+        elapsedUntilPause_ = std::chrono::nanoseconds::zero();
     }
 
     int64_t timeMs() const
     {
-        int64_t msTotal = elapsedUntilPause;
-        if (!paused)
-            msTotal += numeric::dist(startTime, wxGetUTCTimeMillis().GetValue());
-        return msTotal;
+        auto elapsedTotal = elapsedUntilPause_;
+        if (!paused_)
+            elapsedTotal += std::chrono::system_clock::now() - startTime_;
+
+        return std::chrono::duration_cast<std::chrono::milliseconds>(elapsedTotal).count();
     }
 
 private:
-    wxLongLong_t startTime = wxGetUTCTimeMillis().GetValue(); //alas not a steady clock, but something's got to give!
-    bool    paused = false;
-    int64_t elapsedUntilPause = 0;
+    bool paused_ = false;
+    std::chrono::system_clock::time_point startTime_ = std::chrono::system_clock::now(); //uses ::GetSystemTimePreciseAsFileTime()
+    std::chrono::nanoseconds elapsedUntilPause_{}; //std::chrono::duration is uninitialized by default! WTF! When will this stupidity end???
 };
 
 
@@ -1020,7 +1022,7 @@ public:
 
         lastSample = std::make_pair(timeNowMs, value);
 
-        //allow for at most one sample per 100ms (handles duplicate inserts, too!) => this is unrelated to UI_UPDATE_INTERVAL!
+        //allow for at most one sample per 100ms (handles duplicate inserts, too!) => this is unrelated to UI_UPDATE_INTERVAL_MS!
         if (!samples.empty()) //always unconditionally insert first sample!
             if (timeNowMs / 100 == samples.rbegin()->first / 100)
                 return;
@@ -1765,7 +1767,7 @@ void SyncProgressDialogImpl<TopLevelDialog>::updateGuiInt(bool allowYield)
             {
                 wxTheApp->Yield(); //receive UI message that end pause OR forceful termination!
                 //*first* refresh GUI (removing flicker) before sleeping!
-                std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL));
+                std::this_thread::sleep_for(std::chrono::milliseconds(UI_UPDATE_INTERVAL_MS));
             }
             //after SyncProgressDialogImpl::OnClose() called wxWindow::Destroy() on OS X this instance is instantly toast!
             if (wereDead)
@@ -2047,7 +2049,7 @@ void SyncProgressDialogImpl<TopLevelDialog>::processHasFinished(SyncResult resul
         case SyncProgressDialog::RESULT_FINISHED_WITH_SUCCESS:
             if (!soundFileSyncComplete_.empty())
             {
-                const Zstring soundFile = getResourceDir() + soundFileSyncComplete_;
+                const Zstring soundFile = getResourceDirPf() + soundFileSyncComplete_;
                 if (fileExists(soundFile))
                     wxSound::Play(utfCvrtTo<wxString>(soundFile), wxSOUND_ASYNC); //warning: this may fail and show a wxWidgets error message! => must not play when running FFS as batch!
             }
diff --git a/FreeFileSync/Source/ui/small_dlgs.cpp b/FreeFileSync/Source/ui/small_dlgs.cpp
index c59bf681..fdc28196 100644
--- a/FreeFileSync/Source/ui/small_dlgs.cpp
+++ b/FreeFileSync/Source/ui/small_dlgs.cpp
@@ -11,6 +11,7 @@
 #include <zen/stl_tools.h>
 #include <wx/wupdlock.h>
 #include <wx/filedlg.h>
+#include <wx/clipbrd.h>
 #include <wx+/choice_enum.h>
 #include <wx+/bitmap_button.h>
 #include <wx+/rtl.h>
@@ -23,11 +24,13 @@
 #include "gui_generated.h"
 #include "custom_grid.h"
 #include "folder_selector.h"
+#include "version_check.h"
 #include "../algorithm.h"
 #include "../synchronization.h"
 #include "../lib/help_provider.h"
 #include "../lib/hard_filter.h"
 #include "../version/version.h"
+#include "../lib/status_handler.h" //updateUiIsAllowed()
 
 #ifdef ZEN_WIN
     #include <wx+/mouse_move_dlg.h>
@@ -51,6 +54,9 @@ private:
     void OnOK    (wxCommandEvent& event) override { EndModal(ReturnSmallDlg::BUTTON_OKAY); }
     void OnClose (wxCloseEvent&   event) override { EndModal(ReturnSmallDlg::BUTTON_CANCEL); }
     void OnDonate(wxCommandEvent& event) override { wxLaunchDefaultBrowser(L"http://www.freefilesync.org/donate.php"); }
+#ifdef ZEN_WIN
+    void OnShowDonationDetails(wxCommandEvent& event) override { openDonationEditionThankYouPage(this); }
+#endif
 };
 
 
@@ -58,14 +64,43 @@ AboutDlg::AboutDlg(wxWindow* parent) : AboutDlgGenerated(parent)
 {
     setStandardButtonLayout(*bSizerStdButtons, StdButtons().setAffirmative(m_buttonClose));
 
-    setRelativeFontSize(*m_buttonDonate, 1.25);
-
     assert(m_buttonClose->GetId() == wxID_OK); //we cannot use wxID_CLOSE else Esc key won't work: yet another wxWidgets bug??
 
     m_bitmapHomepage->SetBitmap(getResourceImage(L"website"));
     m_bitmapEmail   ->SetBitmap(getResourceImage(L"email"));
     m_bitmapGpl     ->SetBitmap(getResourceImage(L"gpl"));
-    m_bitmapDonate  ->SetBitmap(getResourceImage(L"paypal"));
+
+#ifdef ZEN_WIN
+    std::wstring donorFullName;
+    try
+    {
+        if (Opt<DonationInfo> donationInfo = getDonationInfo()) //throw FileError
+            donorFullName = donationInfo->donorFullName;
+    }
+    catch (const FileError& e)
+    {
+        showNotificationDialog(parent, DialogInfoType::ERROR2, PopupDialogCfg().
+                               setMainInstructions(_("Installation files are corrupted. Please reinstall FreeFileSync.")).
+                               setDetailInstructions(e.toString()));
+    }
+
+    if (!donorFullName.empty())
+    {
+        m_panelDonate->Hide();
+        m_bitmapThanks->SetBitmap(getResourceImage(L"freefilesync-heart"));
+        m_staticTextThanks->SetLabel(replaceCpy(_("Thank you, %x, for your donation and support!"), L"%x", donorFullName));
+        setRelativeFontSize(*m_staticTextThanks, 1.25);
+        setRelativeFontSize(*m_buttonShowDonationDetails, 1.25);
+        m_staticTextThanks->Wrap(260); //*after* changing font size
+    }
+    else
+#endif
+    {
+        m_panelThankYou->Hide();
+        m_bitmapDonate->SetBitmap(getResourceImage(L"paypal"));
+        setRelativeFontSize(*m_staticTextDonate, 1.25);
+        setRelativeFontSize(*m_buttonDonate, 1.25);
+    }
 
     //m_animCtrlWink->SetAnimation(getResourceAnimation(L"wink"));
     //m_animCtrlWink->Play();
@@ -545,12 +580,12 @@ private:
 
     void updateGui();
 
-    const std::vector<const FileSystemObject*>& rowsToDeleteOnLeft;
-    const std::vector<const FileSystemObject*>& rowsToDeleteOnRight;
-    const std::chrono::steady_clock::time_point dlgStartTime = std::chrono::steady_clock::now();
+    const std::vector<const FileSystemObject*>& rowsToDeleteOnLeft_;
+    const std::vector<const FileSystemObject*>& rowsToDeleteOnRight_;
+    const std::chrono::steady_clock::time_point dlgStartTime_ = std::chrono::steady_clock::now();
 
     //output-only parameters:
-    bool& useRecycleBinOut;
+    bool& useRecycleBinOut_;
 };
 
 
@@ -559,9 +594,9 @@ DeleteDialog::DeleteDialog(wxWindow* parent,
                            const std::vector<const FileSystemObject*>& rowsOnRight,
                            bool& useRecycleBin) :
     DeleteDlgGenerated(parent),
-    rowsToDeleteOnLeft(rowsOnLeft),
-    rowsToDeleteOnRight(rowsOnRight),
-    useRecycleBinOut(useRecycleBin)
+    rowsToDeleteOnLeft_(rowsOnLeft),
+    rowsToDeleteOnRight_(rowsOnRight),
+    useRecycleBinOut_(useRecycleBin)
 {
 #ifdef ZEN_WIN
     new zen::MouseMoveWindow(*this); //allow moving main dialog by clicking (nearly) anywhere...; ownership passed to "this"
@@ -593,8 +628,8 @@ void DeleteDialog::updateGui()
     wxWindowUpdateLocker dummy(this); //leads to GUI corruption problems on Linux/OS X!
 #endif
 
-    const std::pair<std::wstring, int> delInfo = zen::getSelectedItemsAsString(rowsToDeleteOnLeft,
-                                                                               rowsToDeleteOnRight);
+    const std::pair<std::wstring, int> delInfo = zen::getSelectedItemsAsString(rowsToDeleteOnLeft_,
+                                                                               rowsToDeleteOnRight_);
     wxString header;
     if (m_checkBoxUseRecycler->GetValue())
     {
@@ -630,10 +665,10 @@ void DeleteDialog::updateGui()
 void DeleteDialog::OnOK(wxCommandEvent& event)
 {
     //additional safety net, similar to Windows Explorer: time delta between DEL and ENTER must be at least 50ms to avoid accidental deletion!
-    if (std::chrono::steady_clock::now() < dlgStartTime + std::chrono::milliseconds(50))
+    if (std::chrono::steady_clock::now() < dlgStartTime_ + std::chrono::milliseconds(50)) //considers chrono-wrap-around!
         return;
 
-    useRecycleBinOut = m_checkBoxUseRecycler->GetValue();
+    useRecycleBinOut_ = m_checkBoxUseRecycler->GetValue();
 
     EndModal(ReturnSmallDlg::BUTTON_OKAY);
 }
@@ -1114,3 +1149,160 @@ ReturnSmallDlg::ButtonPressed zen::showSelectTimespanDlg(wxWindow* parent, std::
     SelectTimespanDlg timeSpanDlg(parent, timeFrom, timeTo);
     return static_cast<ReturnSmallDlg::ButtonPressed>(timeSpanDlg.ShowModal());
 }
+
+//########################################################################################
+
+class ActivationDlg : public ActivationDlgGenerated
+{
+public:
+    ActivationDlg(wxWindow* parent, const std::wstring& lastErrorMsg, const std::wstring& manualActivationUrl, std::wstring& manualActivationKey);
+
+private:
+    void OnActivateOnline (wxCommandEvent& event) override;
+    void OnActivateOffline(wxCommandEvent& event) override;
+    void OnOfflineActivationEnter(wxCommandEvent& event) override { OnActivateOffline(event); }
+    void OnCopyUrl        (wxCommandEvent& event) override;
+    void OnCancel(wxCommandEvent& event) override { EndModal(static_cast<int>(ReturnActivationDlg::CANCEL)); }
+    void OnClose (wxCloseEvent&   event) override { EndModal(static_cast<int>(ReturnActivationDlg::CANCEL)); }
+
+    std::wstring& manualActivationKeyOut_; //in/out parameter
+};
+
+
+ActivationDlg::ActivationDlg(wxWindow* parent,
+                             const std::wstring& lastErrorMsg,
+                             const std::wstring& manualActivationUrl,
+                             std::wstring& manualActivationKey) :
+    ActivationDlgGenerated(parent),
+    manualActivationKeyOut_(manualActivationKey)
+{
+#ifdef ZEN_WIN
+    new zen::MouseMoveWindow(*this); //allow moving main dialog by clicking (nearly) anywhere...; ownership passed to "this"
+#endif
+    setStandardButtonLayout(*bSizerStdButtons, StdButtons().setCancel(m_buttonCancel));
+
+    //setMainInstructionFont(*m_staticTextMain);
+
+    m_bitmapActivation->SetBitmap(getResourceImage(L"website"));
+
+    m_textCtrlLastError           ->ChangeValue(lastErrorMsg);
+    m_textCtrlManualActivationUrl ->ChangeValue(manualActivationUrl);
+    m_textCtrlOfflineActivationKey->ChangeValue(manualActivationKey);
+
+    GetSizer()->SetSizeHints(this); //~=Fit() + SetMinSize()
+    //=> works like a charm for GTK2 with window resizing problems and title bar corruption; e.g. Debian!!!
+    Center(); //needs to be re-applied after a dialog size change!
+
+    m_buttonActivateOnline->SetFocus();
+}
+
+
+void ActivationDlg::OnCopyUrl(wxCommandEvent& event)
+{
+    if (wxClipboard::Get()->Open())
+    {
+        ZEN_ON_SCOPE_EXIT(wxClipboard::Get()->Close());
+        wxClipboard::Get()->SetData(new wxTextDataObject(m_textCtrlManualActivationUrl->GetValue())); //ownership passed
+
+        m_textCtrlManualActivationUrl->SetFocus(); //[!] otherwise selection is lost
+        m_textCtrlManualActivationUrl->SelectAll(); //some visual feedback
+    }
+}
+
+
+void ActivationDlg::OnActivateOnline(wxCommandEvent& event)
+{
+    manualActivationKeyOut_ = m_textCtrlOfflineActivationKey->GetValue();
+    EndModal(static_cast<int>(ReturnActivationDlg::ACTIVATE_ONLINE));
+}
+
+
+void ActivationDlg::OnActivateOffline(wxCommandEvent& event)
+{
+    manualActivationKeyOut_ = m_textCtrlOfflineActivationKey->GetValue();
+    EndModal(static_cast<int>(ReturnActivationDlg::ACTIVATE_OFFLINE));
+}
+
+
+ReturnActivationDlg zen::showActivationDialog(wxWindow* parent, const std::wstring& lastErrorMsg, const std::wstring& manualActivationUrl, std::wstring& manualActivationKey)
+{
+    ActivationDlg dlg(parent, lastErrorMsg, manualActivationUrl, manualActivationKey);
+    return static_cast<ReturnActivationDlg>(dlg.ShowModal());
+}
+
+//########################################################################################
+
+class DownloadProgressWindow::Impl : public DownloadProgressDlgGenerated
+{
+public:
+    Impl(wxWindow* parent, const Zstring& fileName, std::uint64_t fileSize);
+
+    void notifyProgress(std::uint64_t delta) { bytesCurrent_ += delta; }
+
+    void requestUiRefresh() //throw CancelPressed
+    {
+        if (cancelled_)
+            throw CancelPressed();
+
+        if (updateUiIsAllowed())
+        {
+            updateGui();
+            //wxTheApp->Yield();
+            ::wxSafeYield(this); //disables user input except for "this" (using wxWindowDisabler instead would move the FFS main dialog into the background: why?)
+        }
+    }
+
+private:
+    void OnCancel(wxCommandEvent& event) override { cancelled_ = true; }
+
+    void updateGui()
+    {
+        const double fraction = bytesTotal_ == 0 ? 0 : 1.0 * bytesCurrent_ / bytesTotal_;
+        m_staticTextHeader->SetLabel(_("Downloading update...") + L" " +
+                                     numberTo<std::wstring>(numeric::round(fraction * 100)) + L"% (" + filesizeToShortString(bytesCurrent_) + L")");
+        m_gaugeProgress->SetValue(numeric::round(fraction * GAUGE_FULL_RANGE));
+    }
+
+    bool cancelled_ = false;
+    std::uint64_t bytesCurrent_ = 0;
+    const std::uint64_t bytesTotal_;
+    const int GAUGE_FULL_RANGE = 1000000;
+};
+
+
+DownloadProgressWindow::Impl::Impl(wxWindow* parent, const Zstring& filePath, std::uint64_t fileSize) :
+    DownloadProgressDlgGenerated(parent),
+    bytesTotal_(fileSize)
+{
+#ifdef ZEN_WIN
+    new zen::MouseMoveWindow(*this); //allow moving main dialog by clicking (nearly) anywhere...; ownership passed to "this"
+#endif
+
+    setStandardButtonLayout(*bSizerStdButtons, StdButtons().setCancel(m_buttonCancel));
+
+    setMainInstructionFont(*m_staticTextHeader);
+
+    m_bitmapDownloading->SetBitmap(getResourceImage(L"website"));
+
+    m_gaugeProgress->SetRange(GAUGE_FULL_RANGE);
+
+    m_staticTextDetails->SetLabel(utfCvrtTo<std::wstring>(filePath));
+
+    updateGui();
+
+    GetSizer()->SetSizeHints(this); //~=Fit() + SetMinSize()
+    //=> works like a charm for GTK2 with window resizing problems and title bar corruption; e.g. Debian!!!
+    Center(); //needs to be re-applied after a dialog size change!
+    Show();
+
+    m_buttonCancel->SetFocus();
+}
+
+
+zen::DownloadProgressWindow::DownloadProgressWindow(wxWindow* parent, const Zstring& filePath, std::uint64_t fileSize) :
+    pimpl_(new DownloadProgressWindow::Impl(parent, filePath, fileSize)) {}
+
+zen::DownloadProgressWindow::~DownloadProgressWindow() { pimpl_->Destroy(); }
+
+void zen::DownloadProgressWindow::notifyProgress(std::uint64_t delta) { pimpl_->notifyProgress(delta); }
+void zen::DownloadProgressWindow::requestUiRefresh() { pimpl_->requestUiRefresh(); } //throw CancelPressed
diff --git a/FreeFileSync/Source/ui/small_dlgs.h b/FreeFileSync/Source/ui/small_dlgs.h
index 22a3012e..3eb23184 100644
--- a/FreeFileSync/Source/ui/small_dlgs.h
+++ b/FreeFileSync/Source/ui/small_dlgs.h
@@ -57,6 +57,30 @@ ReturnSmallDlg::ButtonPressed showSelectTimespanDlg(wxWindow* parent, std::int64
 #if defined ZEN_WIN_VISTA_AND_LATER || defined ZEN_MAC
     ReturnSmallDlg::ButtonPressed showSftpSetupDialog(wxWindow* parent, Zstring& folderPathPhrase);
 #endif
+
+enum class ReturnActivationDlg
+{
+    CANCEL,
+    ACTIVATE_ONLINE,
+    ACTIVATE_OFFLINE,
+};
+ReturnActivationDlg showActivationDialog(wxWindow* parent, const std::wstring& lastErrorMsg, const std::wstring& manualActivationUrl, std::wstring& manualActivationKey);
+
+
+class DownloadProgressWindow //remporary progress info => life-time: stack
+{
+public:
+    DownloadProgressWindow(wxWindow* parent, const Zstring& filePath, std::uint64_t fileSize);
+    ~DownloadProgressWindow();
+
+    struct CancelPressed {};
+    void requestUiRefresh(); //throw CancelPressed
+    void notifyProgress(std::uint64_t delta);
+
+private:
+    class Impl;
+    Impl* const pimpl_;
+};
 }
 
 #endif //SMALL_DLGS_H_8321790875018750245
diff --git a/FreeFileSync/Source/ui/switch_to_gui.h b/FreeFileSync/Source/ui/switch_to_gui.h
deleted file mode 100644
index 3ef5f6e0..00000000
--- a/FreeFileSync/Source/ui/switch_to_gui.h
+++ /dev/null
@@ -1,45 +0,0 @@
-// *****************************************************************************
-// * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
-// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
-// *****************************************************************************
-
-#ifndef SWITCH_TO_GUI_H_132047815734845
-#define SWITCH_TO_GUI_H_132047815734845
-
-#include "../lib/process_xml.h"
-#include "main_dlg.h" //in "application.cpp" we have this dependency anyway!
-
-
-namespace zen
-{
-//switch from FreeFileSync Batch to GUI modus: opens a new FreeFileSync GUI session asynchronously
-class SwitchToGui
-{
-public:
-    SwitchToGui(const Zstring& globalConfigFile,
-                xmlAccess::XmlGlobalSettings& globalSettings,
-                const Zstring& referenceFile,
-                const xmlAccess::XmlBatchConfig& batchCfg) :
-        globalConfigFile_(globalConfigFile),
-        globalSettings_(globalSettings),
-        guiCfg(xmlAccess::convertBatchToGui(batchCfg))
-    {
-        referenceFiles.push_back(referenceFile);
-    }
-
-    void execute() const
-    {
-        MainDialog::create(globalConfigFile_, &globalSettings_, guiCfg, referenceFiles, /*bool startComparison = */ true); //new toplevel window
-    }
-
-private:
-    const Zstring globalConfigFile_;
-    xmlAccess::XmlGlobalSettings& globalSettings_;
-
-    std::vector<Zstring> referenceFiles;
-    const xmlAccess::XmlGuiConfig guiCfg;
-};
-}
-
-#endif //SWITCH_TO_GUI_H_132047815734845
diff --git a/FreeFileSync/Source/ui/sync_cfg.cpp b/FreeFileSync/Source/ui/sync_cfg.cpp
index 69b35137..9bac8df3 100644
--- a/FreeFileSync/Source/ui/sync_cfg.cpp
+++ b/FreeFileSync/Source/ui/sync_cfg.cpp
@@ -72,9 +72,9 @@ private:
     void OnHelpTimeShift         (wxHyperlinkEvent& event) override { displayHelpEntry(L"daylight-saving-time", this); }
 
     void OnToggleLocalCompSettings(wxCommandEvent& event) override { updateCompGui(); updateSyncGui(); /*affects sync settings, too!*/ }
-    void OnCompByTimeSize         (wxCommandEvent& event) override { localCmpVar = CompareVariant::TIME_SIZE; updateCompGui(); updateSyncGui(); } //
-    void OnCompByContent          (wxCommandEvent& event) override { localCmpVar = CompareVariant::CONTENT;   updateCompGui(); updateSyncGui(); } //affects sync settings, too!
-    void OnCompBySize             (wxCommandEvent& event) override { localCmpVar = CompareVariant::SIZE;      updateCompGui(); updateSyncGui(); } //
+    void OnCompByTimeSize         (wxCommandEvent& event) override { localCmpVar_ = CompareVariant::TIME_SIZE; updateCompGui(); updateSyncGui(); } //
+    void OnCompByContent          (wxCommandEvent& event) override { localCmpVar_ = CompareVariant::CONTENT;   updateCompGui(); updateSyncGui(); } //affects sync settings, too!
+    void OnCompBySize             (wxCommandEvent& event) override { localCmpVar_ = CompareVariant::SIZE;      updateCompGui(); updateSyncGui(); } //
     void OnCompByTimeSizeDouble   (wxMouseEvent&   event) override;
     void OnCompBySizeDouble       (wxMouseEvent&   event) override;
     void OnCompByContentDouble    (wxMouseEvent&   event) override;
@@ -86,7 +86,7 @@ private:
 
     void updateCompGui();
 
-    CompareVariant localCmpVar = CompareVariant::TIME_SIZE;
+    CompareVariant localCmpVar_ = CompareVariant::TIME_SIZE;
 
     //------------- filter panel --------------------------
     void OnHelpShowExamples(wxHyperlinkEvent& event) override { displayHelpEntry(L"exclude-items", this); }
@@ -100,17 +100,17 @@ private:
 
     void updateFilterGui();
 
-    EnumDescrList<UnitTime> enumTimeDescr;
-    EnumDescrList<UnitSize> enumSizeDescr;
+    EnumDescrList<UnitTime> enumTimeDescr_;
+    EnumDescrList<UnitSize> enumSizeDescr_;
 
     //------------- synchronization panel -----------------
-    void OnSyncTwoWay(wxCommandEvent& event) override { directionCfg.var = DirectionConfig::TWO_WAY; updateSyncGui(); }
-    void OnSyncMirror(wxCommandEvent& event) override { directionCfg.var = DirectionConfig::MIRROR;  updateSyncGui(); }
-    void OnSyncUpdate(wxCommandEvent& event) override { directionCfg.var = DirectionConfig::UPDATE;  updateSyncGui(); }
-    void OnSyncCustom(wxCommandEvent& event) override { directionCfg.var = DirectionConfig::CUSTOM;  updateSyncGui(); }
+    void OnSyncTwoWay(wxCommandEvent& event) override { directionCfg_.var = DirectionConfig::TWO_WAY; updateSyncGui(); }
+    void OnSyncMirror(wxCommandEvent& event) override { directionCfg_.var = DirectionConfig::MIRROR;  updateSyncGui(); }
+    void OnSyncUpdate(wxCommandEvent& event) override { directionCfg_.var = DirectionConfig::UPDATE;  updateSyncGui(); }
+    void OnSyncCustom(wxCommandEvent& event) override { directionCfg_.var = DirectionConfig::CUSTOM;  updateSyncGui(); }
 
     void OnToggleLocalSyncSettings(wxCommandEvent& event) override { updateSyncGui(); }
-    void OnToggleDetectMovedFiles (wxCommandEvent& event) override { directionCfg.detectMovedFiles = !directionCfg.detectMovedFiles; updateSyncGui(); } //parameter NOT owned by checkbox!
+    void OnToggleDetectMovedFiles (wxCommandEvent& event) override { directionCfg_.detectMovedFiles = !directionCfg_.detectMovedFiles; updateSyncGui(); } //parameter NOT owned by checkbox!
     void OnChangeSyncOption       (wxCommandEvent& event) override { updateSyncGui(); }
 
     void OnSyncTwoWayDouble(wxMouseEvent& event) override;
@@ -125,11 +125,11 @@ private:
     void OnDifferent      (wxCommandEvent& event) override;
     void OnConflict       (wxCommandEvent& event) override;
 
-    void OnDeletionPermanent  (wxCommandEvent& event) override { handleDeletion = DeletionPolicy::PERMANENT;  updateSyncGui(); }
-    void OnDeletionRecycler   (wxCommandEvent& event) override { handleDeletion = DeletionPolicy::RECYCLER;   updateSyncGui(); }
-    void OnDeletionVersioning (wxCommandEvent& event) override { handleDeletion = DeletionPolicy::VERSIONING; updateSyncGui(); }
+    void OnDeletionPermanent  (wxCommandEvent& event) override { handleDeletion_ = DeletionPolicy::PERMANENT;  updateSyncGui(); }
+    void OnDeletionRecycler   (wxCommandEvent& event) override { handleDeletion_ = DeletionPolicy::RECYCLER;   updateSyncGui(); }
+    void OnDeletionVersioning (wxCommandEvent& event) override { handleDeletion_ = DeletionPolicy::VERSIONING; updateSyncGui(); }
 
-    void OnToggleDeletionType(wxCommandEvent& event) override { toggleDeletionPolicy(handleDeletion); updateSyncGui(); }
+    void OnToggleDeletionType(wxCommandEvent& event) override { toggleDeletionPolicy(handleDeletion_); updateSyncGui(); }
 
     void OnHelpDetectMovedFiles(wxHyperlinkEvent& event) override { displayHelpEntry(L"synchronization-settings" , this); }
     void OnHelpVersioning      (wxHyperlinkEvent& event) override { displayHelpEntry(L"versioning", this); }
@@ -141,8 +141,8 @@ private:
 
     //-----------------------------------------------------
 
-    void OnErrorPopup (wxCommandEvent& event) override { onGuiError = ON_GUIERROR_POPUP;  updateMiscGui(); } //parameter NOT owned by radio button
-    void OnErrorIgnore(wxCommandEvent& event) override { onGuiError = ON_GUIERROR_IGNORE; updateMiscGui(); } //
+    void OnErrorPopup (wxCommandEvent& event) override { onGuiError_ = ON_GUIERROR_POPUP;  updateMiscGui(); } //parameter NOT owned by radio button
+    void OnErrorIgnore(wxCommandEvent& event) override { onGuiError_ = ON_GUIERROR_IGNORE; updateMiscGui(); } //
 
     MiscSyncConfig getMiscSyncOptions() const;
     void setMiscSyncOptions(const MiscSyncConfig& miscCfg);
@@ -150,12 +150,12 @@ private:
     void updateMiscGui();
 
     //parameters with ownership NOT within GUI controls!
-    DirectionConfig directionCfg;
-    DeletionPolicy handleDeletion = DeletionPolicy::RECYCLER; //use Recycler, delete permanently or move to user-defined location
-    OnGuiError onGuiError = ON_GUIERROR_POPUP;
+    DirectionConfig directionCfg_;
+    DeletionPolicy handleDeletion_ = DeletionPolicy::RECYCLER; //use Recycler, delete permanently or move to user-defined location
+    OnGuiError onGuiError_ = ON_GUIERROR_POPUP;
 
-    EnumDescrList<VersioningStyle> enumVersioningStyle;
-    FolderSelector versioningFolder;
+    EnumDescrList<VersioningStyle> enumVersioningStyle_;
+    FolderSelector versioningFolder_;
 
     //-----------------------------------------------------
 
@@ -163,14 +163,14 @@ private:
     bool unselectFolderPairConfig(); //returns false on error: shows message box!
 
     //output-only parameters
-    GlobalSyncConfig& globalCfgOut;
-    std::vector<LocalPairConfig>& folderPairConfigOut;
+    GlobalSyncConfig& globalCfgOut_;
+    std::vector<LocalPairConfig>& folderPairConfigOut_;
 
     //working copy of ALL config parameters: only one folder pair is selected at a time!
     GlobalSyncConfig globalCfg_;
     std::vector<LocalPairConfig> folderPairConfig_;
 
-    int selectedPairIndexToShow = EMPTY_PAIR_INDEX_SELECTED;
+    int selectedPairIndexToShow_ = EMPTY_PAIR_INDEX_SELECTED;
     static const int EMPTY_PAIR_INDEX_SELECTED = -2;
 
     const size_t onCompletionHistoryMax_;
@@ -219,9 +219,9 @@ ConfigDialog::ConfigDialog(wxWindow* parent,
                            GlobalSyncConfig& globalCfg,
                            size_t onCompletionHistoryMax) :
     ConfigDlgGenerated(parent),
-    versioningFolder(*m_panelVersioning, *m_buttonSelectVersioningFolder, *m_bpButtonSelectAltFolder, *m_versioningFolderPath, nullptr /*staticText*/, nullptr /*wxWindow*/),
-    globalCfgOut(globalCfg),
-    folderPairConfigOut(folderPairConfig),
+    versioningFolder_(*m_panelVersioning, *m_buttonSelectVersioningFolder, *m_bpButtonSelectAltFolder, *m_versioningFolderPath, nullptr /*staticText*/, nullptr /*dropWindow2*/),
+    globalCfgOut_(globalCfg),
+    folderPairConfigOut_(folderPairConfig),
     globalCfg_(globalCfg),
     folderPairConfig_(folderPairConfig),
     onCompletionHistoryMax_(onCompletionHistoryMax)
@@ -282,7 +282,7 @@ ConfigDialog::ConfigDialog(wxWindow* parent,
     m_textCtrlInclude->Connect(wxEVT_KEY_DOWN, wxKeyEventHandler(ConfigDialog::onFilterKeyEvent), nullptr, this);
     m_textCtrlExclude->Connect(wxEVT_KEY_DOWN, wxKeyEventHandler(ConfigDialog::onFilterKeyEvent), nullptr, this);
 
-    enumTimeDescr.
+    enumTimeDescr_.
     add(UnitTime::NONE, L"(" + _("None") + L")"). //meta options should be enclosed in parentheses
     add(UnitTime::TODAY,       _("Today")).
     //add(UnitTime::THIS_WEEK,   _("This week")).
@@ -290,7 +290,7 @@ ConfigDialog::ConfigDialog(wxWindow* parent,
     add(UnitTime::THIS_YEAR,   _("This year")).
     add(UnitTime::LAST_X_DAYS, _("Last x days"));
 
-    enumSizeDescr.
+    enumSizeDescr_.
     add(UnitSize::NONE, L"(" + _("None") + L")"). //meta options should be enclosed in parentheses
     add(UnitSize::BYTE, _("Byte")).
     add(UnitSize::KB,   _("KB")).
@@ -319,7 +319,7 @@ ConfigDialog::ConfigDialog(wxWindow* parent,
     setRelativeFontSize(*m_toggleBtnUpdate, 1.25);
     setRelativeFontSize(*m_toggleBtnCustom, 1.25);
 
-    enumVersioningStyle.
+    enumVersioningStyle_.
     add(VersioningStyle::REPLACE,       _("Replace"),    _("Move files and replace if existing")).
     add(VersioningStyle::ADD_TIMESTAMP, _("Time stamp"), _("Append a time stamp to each file name"));
 
@@ -444,7 +444,7 @@ void ConfigDialog::OnSelectFolderPair(wxCommandEvent& event)
     if (!unselectFolderPairConfig())
     {
         //restore old selection:
-        m_listBoxFolderPair->SetSelection(selectedPairIndexToShow + 1);
+        m_listBoxFolderPair->SetSelection(selectedPairIndexToShow_ + 1);
         return;
     }
     selectFolderPairConfig(selPos - 1);
@@ -493,7 +493,7 @@ std::shared_ptr<const CompConfig> ConfigDialog::getCompConfig() const
         return nullptr;
 
     CompConfig compCfg;
-    compCfg.compareVar = localCmpVar;
+    compCfg.compareVar = localCmpVar_;
     compCfg.handleSymlinks = !m_checkBoxSymlinksInclude->GetValue() ? SymLinkHandling::EXCLUDE : m_radioBtnSymlinksDirect->GetValue() ? SymLinkHandling::DIRECT : SymLinkHandling::FOLLOW;
     compCfg.ignoreTimeShiftMinutes = fromTimeShiftPhrase(copyStringTo<std::wstring>(m_textCtrlTimeShift->GetValue()));
 
@@ -508,7 +508,7 @@ void ConfigDialog::setCompConfig(std::shared_ptr<const CompConfig> compCfg)
     if (!compCfg) //when local settings are inactive, display (current) global settings instead:
         compCfg = std::make_shared<const CompConfig>(globalCfg_.cmpConfig);
 
-    localCmpVar = compCfg->compareVar;
+    localCmpVar_ = compCfg->compareVar;
 
     switch (compCfg->handleSymlinks)
     {
@@ -545,7 +545,7 @@ void ConfigDialog::updateCompGui()
     m_toggleBtnByContent ->SetValue(false);
 
     if (m_checkBoxUseLocalCmpOptions->GetValue()) //help wxWidgets a little to render inactive config state (need on Windows, NOT on Linux!)
-        switch (localCmpVar)
+        switch (localCmpVar_)
         {
             case CompareVariant::TIME_SIZE:
                 m_toggleBtnByTimeSize->SetValue(true);
@@ -566,12 +566,12 @@ void ConfigDialog::updateCompGui()
         else
             bmpCtrl.SetBitmap(greyScale(bmp));
     };
-    setBitmap(*m_bitmapByTimeSize, localCmpVar == CompareVariant::TIME_SIZE, getResourceImage(L"file-time"));
-    setBitmap(*m_bitmapByContent,  localCmpVar == CompareVariant::CONTENT,   getResourceImage(L"file-content"));
-    setBitmap(*m_bitmapBySize,     localCmpVar == CompareVariant::SIZE,      getResourceImage(L"file-size"));
+    setBitmap(*m_bitmapByTimeSize, localCmpVar_ == CompareVariant::TIME_SIZE, getResourceImage(L"file-time"));
+    setBitmap(*m_bitmapByContent,  localCmpVar_ == CompareVariant::CONTENT,   getResourceImage(L"file-content"));
+    setBitmap(*m_bitmapBySize,     localCmpVar_ == CompareVariant::SIZE,      getResourceImage(L"file-size"));
 
     //active variant description:
-    setText(*m_textCtrlCompVarDescription, L"\n" + getCompVariantDescription(localCmpVar));
+    setText(*m_textCtrlCompVarDescription, L"\n" + getCompVariantDescription(localCmpVar_));
 
     m_radioBtnSymlinksDirect->Enable(m_checkBoxSymlinksInclude->GetValue());
     m_radioBtnSymlinksFollow->Enable(m_checkBoxSymlinksInclude->GetValue());
@@ -611,11 +611,11 @@ FilterConfig ConfigDialog::getFilterConfig() const
 
     return FilterConfig(includeFilter, exludeFilter,
                         m_spinCtrlTimespan->GetValue(),
-                        getEnumVal(enumTimeDescr, *m_choiceUnitTimespan),
+                        getEnumVal(enumTimeDescr_, *m_choiceUnitTimespan),
                         m_spinCtrlMinSize->GetValue(),
-                        getEnumVal(enumSizeDescr, *m_choiceUnitMinSize),
+                        getEnumVal(enumSizeDescr_, *m_choiceUnitMinSize),
                         m_spinCtrlMaxSize->GetValue(),
-                        getEnumVal(enumSizeDescr, *m_choiceUnitMaxSize));
+                        getEnumVal(enumSizeDescr_, *m_choiceUnitMaxSize));
 }
 
 
@@ -624,9 +624,9 @@ void ConfigDialog::setFilterConfig(const FilterConfig& filter)
     m_textCtrlInclude->ChangeValue(utfCvrtTo<wxString>(filter.includeFilter));
     m_textCtrlExclude->ChangeValue(utfCvrtTo<wxString>(filter.excludeFilter));
 
-    setEnumVal(enumTimeDescr, *m_choiceUnitTimespan, filter.unitTimeSpan);
-    setEnumVal(enumSizeDescr, *m_choiceUnitMinSize,  filter.unitSizeMin);
-    setEnumVal(enumSizeDescr, *m_choiceUnitMaxSize,  filter.unitSizeMax);
+    setEnumVal(enumTimeDescr_, *m_choiceUnitTimespan, filter.unitTimeSpan);
+    setEnumVal(enumSizeDescr_, *m_choiceUnitMinSize,  filter.unitSizeMin);
+    setEnumVal(enumSizeDescr_, *m_choiceUnitMaxSize,  filter.unitSizeMax);
 
     m_spinCtrlTimespan->SetValue(static_cast<int>(filter.timeSpan));
     m_spinCtrlMinSize ->SetValue(static_cast<int>(filter.sizeMin));
@@ -754,42 +754,42 @@ void toggleCustomSyncConfig(DirectionConfig& directionCfg, SyncDirection& custSy
 
 void ConfigDialog::OnExLeftSideOnly(wxCommandEvent& event)
 {
-    toggleCustomSyncConfig(directionCfg, directionCfg.custom.exLeftSideOnly);
+    toggleCustomSyncConfig(directionCfg_, directionCfg_.custom.exLeftSideOnly);
     updateSyncGui();
 }
 
 
 void ConfigDialog::OnExRightSideOnly(wxCommandEvent& event)
 {
-    toggleCustomSyncConfig(directionCfg, directionCfg.custom.exRightSideOnly);
+    toggleCustomSyncConfig(directionCfg_, directionCfg_.custom.exRightSideOnly);
     updateSyncGui();
 }
 
 
 void ConfigDialog::OnLeftNewer(wxCommandEvent& event)
 {
-    toggleCustomSyncConfig(directionCfg, directionCfg.custom.leftNewer);
+    toggleCustomSyncConfig(directionCfg_, directionCfg_.custom.leftNewer);
     updateSyncGui();
 }
 
 
 void ConfigDialog::OnRightNewer(wxCommandEvent& event)
 {
-    toggleCustomSyncConfig(directionCfg, directionCfg.custom.rightNewer);
+    toggleCustomSyncConfig(directionCfg_, directionCfg_.custom.rightNewer);
     updateSyncGui();
 }
 
 
 void ConfigDialog::OnDifferent(wxCommandEvent& event)
 {
-    toggleCustomSyncConfig(directionCfg, directionCfg.custom.different);
+    toggleCustomSyncConfig(directionCfg_, directionCfg_.custom.different);
     updateSyncGui();
 }
 
 
 void ConfigDialog::OnConflict(wxCommandEvent& event)
 {
-    toggleCustomSyncConfig(directionCfg, directionCfg.custom.conflict);
+    toggleCustomSyncConfig(directionCfg_, directionCfg_.custom.conflict);
     updateSyncGui();
 }
 
@@ -878,10 +878,10 @@ std::shared_ptr<const SyncConfig> ConfigDialog::getSyncConfig() const
         return nullptr;
 
     SyncConfig syncCfg;
-    syncCfg.directionCfg           = directionCfg;
-    syncCfg.handleDeletion         = handleDeletion;
-    syncCfg.versioningFolderPhrase = versioningFolder.getPath();
-    syncCfg.versioningStyle        = getEnumVal(enumVersioningStyle, *m_choiceVersioningStyle);
+    syncCfg.directionCfg           = directionCfg_;
+    syncCfg.handleDeletion         = handleDeletion_;
+    syncCfg.versioningFolderPhrase = versioningFolder_.getPath();
+    syncCfg.versioningStyle        = getEnumVal(enumVersioningStyle_, *m_choiceVersioningStyle);
 
     return std::make_shared<const SyncConfig>(syncCfg);
 }
@@ -894,10 +894,10 @@ void ConfigDialog::setSyncConfig(std::shared_ptr<const SyncConfig> syncCfg)
     if (!syncCfg) //when local settings are inactive, display (current) global settings instead:
         syncCfg = std::make_shared<const SyncConfig>(globalCfg_.syncCfg);
 
-    directionCfg   = syncCfg->directionCfg; //make working copy; ownership *not* on GUI
-    handleDeletion = syncCfg->handleDeletion;
-    versioningFolder.setPath(syncCfg->versioningFolderPhrase);
-    setEnumVal(enumVersioningStyle, *m_choiceVersioningStyle, syncCfg->versioningStyle);
+    directionCfg_   = syncCfg->directionCfg; //make working copy; ownership *not* on GUI
+    handleDeletion_ = syncCfg->handleDeletion;
+    versioningFolder_.setPath(syncCfg->versioningFolderPhrase);
+    setEnumVal(enumVersioningStyle_, *m_choiceVersioningStyle, syncCfg->versioningStyle);
 
     updateSyncGui();
 }
@@ -921,7 +921,7 @@ void ConfigDialog::updateSyncGui()
     m_notebook->SetPageImage(static_cast<size_t>(SyncConfigPanel::SYNC),
                              static_cast<int>(m_checkBoxUseLocalSyncOptions->GetValue() ? ConfigTypeImage::SYNC: ConfigTypeImage::SYNC_GREY));
 
-    updateSyncDirectionIcons(directionCfg,
+    updateSyncDirectionIcons(directionCfg_,
                              *m_bpButtonLeftOnly,
                              *m_bpButtonRightOnly,
                              *m_bpButtonLeftNewer,
@@ -930,8 +930,8 @@ void ConfigDialog::updateSyncGui()
                              *m_bpButtonConflict);
 
     //selecting "detect move files" does not always make sense:
-    m_checkBoxDetectMove->Enable(detectMovedFilesSelectable(directionCfg));
-    m_checkBoxDetectMove->SetValue(detectMovedFilesEnabled(directionCfg)); //parameter NOT owned by checkbox!
+    m_checkBoxDetectMove->Enable(detectMovedFilesSelectable(directionCfg_));
+    m_checkBoxDetectMove->SetValue(detectMovedFilesEnabled(directionCfg_)); //parameter NOT owned by checkbox!
 
     auto setBitmap = [&](wxStaticBitmap& bmpCtrl, bool active, const wxBitmap& bmp)
     {
@@ -943,14 +943,14 @@ void ConfigDialog::updateSyncGui()
     };
 
     //display only relevant sync options
-    m_bitmapDatabase     ->Show(directionCfg.var == DirectionConfig::TWO_WAY);
-    fgSizerSyncDirections->Show(directionCfg.var != DirectionConfig::TWO_WAY);
+    m_bitmapDatabase     ->Show(directionCfg_.var == DirectionConfig::TWO_WAY);
+    fgSizerSyncDirections->Show(directionCfg_.var != DirectionConfig::TWO_WAY);
 
-    if (directionCfg.var == DirectionConfig::TWO_WAY)
+    if (directionCfg_.var == DirectionConfig::TWO_WAY)
         setBitmap(*m_bitmapDatabase, true, getResourceImage(L"database"));
     else
     {
-        const CompareVariant activeCmpVar = m_checkBoxUseLocalCmpOptions->GetValue() ? localCmpVar : globalCfg_.cmpConfig.compareVar;
+        const CompareVariant activeCmpVar = m_checkBoxUseLocalCmpOptions->GetValue() ? localCmpVar_ : globalCfg_.cmpConfig.compareVar;
 
         m_bitmapLeftNewer   ->Show(activeCmpVar == CompareVariant::TIME_SIZE);
         m_bpButtonLeftNewer ->Show(activeCmpVar == CompareVariant::TIME_SIZE);
@@ -962,7 +962,7 @@ void ConfigDialog::updateSyncGui()
     }
 
     //active variant description:
-    setText(*m_textCtrlSyncVarDescription, L"\n" + getSyncVariantDescription(directionCfg.var));
+    setText(*m_textCtrlSyncVarDescription, L"\n" + getSyncVariantDescription(directionCfg_.var));
 
     //update toggle buttons -> they have no parameter-ownership at all!
     m_toggleBtnTwoWay->SetValue(false);
@@ -971,7 +971,7 @@ void ConfigDialog::updateSyncGui()
     m_toggleBtnCustom->SetValue(false);
 
     if (m_checkBoxUseLocalSyncOptions->GetValue()) //help wxWidgets a little to render inactive config state (need on Windows, NOT on Linux!)
-        switch (directionCfg.var)
+        switch (directionCfg_.var)
         {
             case DirectionConfig::TWO_WAY:
                 m_toggleBtnTwoWay->SetValue(true);
@@ -987,7 +987,7 @@ void ConfigDialog::updateSyncGui()
                 break;
         }
 
-    switch (handleDeletion)
+    switch (handleDeletion_)
     {
         case DeletionPolicy::PERMANENT:
             m_radioBtnPermanent->SetValue(true);
@@ -1011,15 +1011,15 @@ void ConfigDialog::updateSyncGui()
     m_bpButtonDeletionType->SetBitmapDisabled(greyScale(m_bpButtonDeletionType->GetBitmap())); //fix wxWidgets' all-too-clever multi-state!
 
 
-    const bool versioningSelected = handleDeletion == DeletionPolicy::VERSIONING;
+    const bool versioningSelected = handleDeletion_ == DeletionPolicy::VERSIONING;
     m_panelVersioning->Show(versioningSelected);
 
     if (versioningSelected)
     {
-        updateTooltipEnumVal(enumVersioningStyle, *m_choiceVersioningStyle);
+        updateTooltipEnumVal(enumVersioningStyle_, *m_choiceVersioningStyle);
 
         const std::wstring pathSep = utfCvrtTo<std::wstring>(FILE_NAME_SEPARATOR);
-        switch (getEnumVal(enumVersioningStyle, *m_choiceVersioningStyle))
+        switch (getEnumVal(enumVersioningStyle_, *m_choiceVersioningStyle))
         {
             case VersioningStyle::REPLACE:
                 setText(*m_staticTextNamingCvtPart1, pathSep + _("Folder") + pathSep + _("File") + L".doc");
@@ -1043,10 +1043,10 @@ void ConfigDialog::updateSyncGui()
 
 MiscSyncConfig ConfigDialog::getMiscSyncOptions() const
 {
-    assert(selectedPairIndexToShow == -1);
+    assert(selectedPairIndexToShow_ == -1);
 
     MiscSyncConfig miscCfg;
-    miscCfg.handleError         = onGuiError;
+    miscCfg.handleError         = onGuiError_;
     miscCfg.onCompletionCommand = m_comboBoxOnCompletion->getValue();
     miscCfg.onCompletionHistory = m_comboBoxOnCompletion->getHistory();
     return miscCfg;
@@ -1055,7 +1055,7 @@ MiscSyncConfig ConfigDialog::getMiscSyncOptions() const
 
 void ConfigDialog::setMiscSyncOptions(const MiscSyncConfig& miscCfg)
 {
-    onGuiError = miscCfg.handleError;
+    onGuiError_ = miscCfg.handleError;
     m_comboBoxOnCompletion->setValue(miscCfg.onCompletionCommand);
     m_comboBoxOnCompletion->setHistory(miscCfg.onCompletionHistory, onCompletionHistoryMax_);
 
@@ -1065,7 +1065,7 @@ void ConfigDialog::setMiscSyncOptions(const MiscSyncConfig& miscCfg)
 
 void ConfigDialog::updateMiscGui()
 {
-    switch (onGuiError)
+    switch (onGuiError_)
     {
         case ON_GUIERROR_IGNORE:
             m_radioBtnIgnoreErrors->SetValue(true);
@@ -1079,11 +1079,11 @@ void ConfigDialog::updateMiscGui()
 
 void ConfigDialog::selectFolderPairConfig(int newPairIndexToShow)
 {
-    assert(selectedPairIndexToShow == EMPTY_PAIR_INDEX_SELECTED);
+    assert(selectedPairIndexToShow_ == EMPTY_PAIR_INDEX_SELECTED);
     assert(newPairIndexToShow == -1 || makeUnsigned(newPairIndexToShow) < folderPairConfig_.size());
     numeric::clamp(newPairIndexToShow, -1, static_cast<int>(folderPairConfig_.size()) - 1);
 
-    selectedPairIndexToShow = newPairIndexToShow;
+    selectedPairIndexToShow_ = newPairIndexToShow;
     m_listBoxFolderPair->SetSelection(newPairIndexToShow + 1);
 
     //show/hide controls that are only relevant for main/local config
@@ -1116,16 +1116,16 @@ void ConfigDialog::selectFolderPairConfig(int newPairIndexToShow)
     }
     else
     {
-        setCompConfig  (folderPairConfig_[selectedPairIndexToShow].altCmpConfig);
-        setSyncConfig  (folderPairConfig_[selectedPairIndexToShow].altSyncConfig);
-        setFilterConfig(folderPairConfig_[selectedPairIndexToShow].localFilter);
+        setCompConfig  (folderPairConfig_[selectedPairIndexToShow_].altCmpConfig);
+        setSyncConfig  (folderPairConfig_[selectedPairIndexToShow_].altSyncConfig);
+        setFilterConfig(folderPairConfig_[selectedPairIndexToShow_].localFilter);
     }
 }
 
 
 bool ConfigDialog::unselectFolderPairConfig()
 {
-    assert(selectedPairIndexToShow == -1 ||  makeUnsigned(selectedPairIndexToShow) < folderPairConfig_.size());
+    assert(selectedPairIndexToShow_ == -1 ||  makeUnsigned(selectedPairIndexToShow_) < folderPairConfig_.size());
 
     auto compCfg   = getCompConfig();
     auto syncCfg   = getSyncConfig();
@@ -1152,7 +1152,7 @@ bool ConfigDialog::unselectFolderPairConfig()
 
     m_comboBoxOnCompletion->addItemHistory(); //commit current "on completion" history item
 
-    if (selectedPairIndexToShow < 0)
+    if (selectedPairIndexToShow_ < 0)
     {
         globalCfg_.cmpConfig = *compCfg;
         globalCfg_.syncCfg   = *syncCfg;
@@ -1161,12 +1161,12 @@ bool ConfigDialog::unselectFolderPairConfig()
     }
     else
     {
-        folderPairConfig_[selectedPairIndexToShow].altCmpConfig  = compCfg;
-        folderPairConfig_[selectedPairIndexToShow].altSyncConfig = syncCfg;
-        folderPairConfig_[selectedPairIndexToShow].localFilter   = filterCfg;
+        folderPairConfig_[selectedPairIndexToShow_].altCmpConfig  = compCfg;
+        folderPairConfig_[selectedPairIndexToShow_].altSyncConfig = syncCfg;
+        folderPairConfig_[selectedPairIndexToShow_].localFilter   = filterCfg;
     }
 
-    selectedPairIndexToShow = EMPTY_PAIR_INDEX_SELECTED;
+    selectedPairIndexToShow_ = EMPTY_PAIR_INDEX_SELECTED;
     //m_listBoxFolderPair->SetSelection(wxNOT_FOUND); not needed, selectedPairIndexToShow has parameter ownership
     return true;
 }
@@ -1177,8 +1177,8 @@ void ConfigDialog::OnOkay(wxCommandEvent& event)
     if (!unselectFolderPairConfig())
         return;
 
-    globalCfgOut        = globalCfg_;
-    folderPairConfigOut = folderPairConfig_;
+    globalCfgOut_        = globalCfg_;
+    folderPairConfigOut_ = folderPairConfig_;
 
     EndModal(ReturnSyncConfig::BUTTON_OKAY);
 }
diff --git a/FreeFileSync/Source/ui/taskbar.cpp b/FreeFileSync/Source/ui/taskbar.cpp
index e8a61efa..1723957a 100644
--- a/FreeFileSync/Source/ui/taskbar.cpp
+++ b/FreeFileSync/Source/ui/taskbar.cpp
@@ -86,7 +86,7 @@ public:
     void setProgress(double fraction)
     {
         const wchar_t* errorMsg = nullptr;
-        setProgress_(assocWindow, fraction * 100000, 100000, errorMsg);
+        setProgress_(assocWindow, fraction * 1000000, 1000000, errorMsg);
         if (errorMsg)
         {
             ZEN_ON_SCOPE_EXIT(freeString_(errorMsg));
diff --git a/FreeFileSync/Source/ui/tree_view.cpp b/FreeFileSync/Source/ui/tree_view.cpp
index 88d4dd49..cbfb5305 100644
--- a/FreeFileSync/Source/ui/tree_view.cpp
+++ b/FreeFileSync/Source/ui/tree_view.cpp
@@ -299,17 +299,15 @@ void TreeView::sortSingleLevel(std::vector<TreeLine>& items, ColumnTypeNavi colu
 
     switch (columnType)
     {
-        case ColumnTypeNavi::BYTES:
-            std::sort(items.begin(), items.end(), makeSortDirection(lessBytes, Int2Type<ascending>()));
-            break;
-
-        case ColumnTypeNavi::DIRECTORY:
+        case ColumnTypeNavi::FOLDER_NAME:
             std::sort(items.begin(), items.end(), LessShortName<ascending>());
             break;
-
         case ColumnTypeNavi::ITEM_COUNT:
             std::sort(items.begin(), items.end(), makeSortDirection(lessCount, Int2Type<ascending>()));
             break;
+        case ColumnTypeNavi::BYTES:
+            std::sort(items.begin(), items.end(), makeSortDirection(lessBytes, Int2Type<ascending>()));
+            break;
     }
 }
 
@@ -467,12 +465,12 @@ bool TreeView::getDefaultSortDirection(ColumnTypeNavi colType)
 {
     switch (colType)
     {
-        case ColumnTypeNavi::BYTES:
-            return false;
-        case ColumnTypeNavi::DIRECTORY:
+        case ColumnTypeNavi::FOLDER_NAME:
             return true;
         case ColumnTypeNavi::ITEM_COUNT:
             return false;
+        case ColumnTypeNavi::BYTES:
+            return false;
     }
     assert(false);
     return true;
@@ -808,11 +806,7 @@ private:
     {
         switch (static_cast<ColumnTypeNavi>(colType))
         {
-            case ColumnTypeNavi::BYTES:
-            case ColumnTypeNavi::ITEM_COUNT:
-                break;
-
-            case ColumnTypeNavi::DIRECTORY:
+            case ColumnTypeNavi::FOLDER_NAME:
                 if (treeDataView_)
                     if (std::unique_ptr<TreeView::Node> node = treeDataView_->getLine(row))
                         if (const TreeView::RootNode* root = dynamic_cast<const TreeView::RootNode*>(node.get()))
@@ -826,6 +820,10 @@ private:
                             return dirLeft + L" \u2212 \n" + dirRight; //\u2212 = unicode minus
                         }
                 break;
+
+            case ColumnTypeNavi::ITEM_COUNT:
+            case ColumnTypeNavi::BYTES:
+                break;
         }
         return std::wstring();
     }
@@ -837,10 +835,7 @@ private:
             if (std::unique_ptr<TreeView::Node> node = treeDataView_->getLine(row))
                 switch (static_cast<ColumnTypeNavi>(colType))
                 {
-                    case ColumnTypeNavi::BYTES:
-                        return filesizeToShortString(node->bytes_);
-
-                    case ColumnTypeNavi::DIRECTORY:
+                    case ColumnTypeNavi::FOLDER_NAME:
                         if (const TreeView::RootNode* root = dynamic_cast<const TreeView::RootNode*>(node.get()))
                             return root->displayName_;
                         else if (const TreeView::DirNode* dir = dynamic_cast<const TreeView::DirNode*>(node.get()))
@@ -851,6 +846,9 @@ private:
 
                     case ColumnTypeNavi::ITEM_COUNT:
                         return toGuiString(node->itemCount_);
+
+                    case ColumnTypeNavi::BYTES:
+                        return filesizeToShortString(node->bytes_);
                 }
         }
         return std::wstring();
@@ -908,7 +906,7 @@ private:
         //   --------------------------------------------------------------------------------
         // -> synchronize renderCell() <-> getBestSize() <-> getRowMouseHover()
 
-        if (static_cast<ColumnTypeNavi>(colType) == ColumnTypeNavi::DIRECTORY && treeDataView_)
+        if (static_cast<ColumnTypeNavi>(colType) == ColumnTypeNavi::FOLDER_NAME && treeDataView_)
         {
             if (std::unique_ptr<TreeView::Node> node = treeDataView_->getLine(row))
             {
@@ -1047,7 +1045,7 @@ private:
     {
         // -> synchronize renderCell() <-> getBestSize() <-> getRowMouseHover()
 
-        if (static_cast<ColumnTypeNavi>(colType) == ColumnTypeNavi::DIRECTORY && treeDataView_)
+        if (static_cast<ColumnTypeNavi>(colType) == ColumnTypeNavi::FOLDER_NAME && treeDataView_)
         {
             if (std::unique_ptr<TreeView::Node> node = treeDataView_->getLine(row))
                 return node->level_ * widthLevelStep + GAP_SIZE + (showPercentBar ? WIDTH_PERCENTAGE_BAR + 2 * GAP_SIZE : 0) + widthNodeStatus + GAP_SIZE
@@ -1065,11 +1063,7 @@ private:
     {
         switch (static_cast<ColumnTypeNavi>(colType))
         {
-            case ColumnTypeNavi::BYTES:
-            case ColumnTypeNavi::ITEM_COUNT:
-                break;
-
-            case ColumnTypeNavi::DIRECTORY:
+            case ColumnTypeNavi::FOLDER_NAME:
                 if (treeDataView_)
                     if (std::unique_ptr<TreeView::Node> node = treeDataView_->getLine(row))
                     {
@@ -1082,6 +1076,10 @@ private:
                             return static_cast<HoverArea>(HoverAreaNavi::NODE);
                     }
                 break;
+
+            case ColumnTypeNavi::ITEM_COUNT:
+            case ColumnTypeNavi::BYTES:
+                break;
         }
         return HoverArea::NONE;
     }
@@ -1090,12 +1088,12 @@ private:
     {
         switch (static_cast<ColumnTypeNavi>(colType))
         {
-            case ColumnTypeNavi::BYTES:
-                return _("Size");
-            case ColumnTypeNavi::DIRECTORY:
+            case ColumnTypeNavi::FOLDER_NAME:
                 return _("Name");
             case ColumnTypeNavi::ITEM_COUNT:
                 return _("Items");
+            case ColumnTypeNavi::BYTES:
+                return _("Size");
         }
         return std::wstring();
     }
@@ -1206,19 +1204,33 @@ private:
         {
             auto colAttr = grid_.getColumnConfig();
 
+            Grid::ColumnAttribute* caFolderName = nullptr;
+            Grid::ColumnAttribute* caToggle     = nullptr;
+
             for (Grid::ColumnAttribute& ca : colAttr)
-                if (ca.type_ == ct)
-                {
-                    ca.visible_ = !ca.visible_;
-                    grid_.setColumnConfig(colAttr);
-                    return;
-                }
+                if (ca.type_ == static_cast<ColumnType>(ColumnTypeNavi::FOLDER_NAME))
+                    caFolderName = &ca;
+                else if (ca.type_ == ct)
+                    caToggle = &ca;
+
+            assert(caFolderName && caFolderName->stretch_ > 0 && caFolderName->visible_);
+            assert(caToggle     && caToggle->stretch_ == 0);
+
+            if (caFolderName && caToggle)
+            {
+                caToggle->visible_ = !caToggle->visible_;
+
+                //take width of newly visible column from stretched folder name column
+                caFolderName->offset_ -= caToggle->visible_ ? caToggle->offset_ : -caToggle->offset_;
+
+                grid_.setColumnConfig(colAttr);
+            }
         };
 
         for (const Grid::ColumnAttribute& ca : grid_.getColumnConfig())
         {
-            menu.addCheckBox(getColumnLabel(ca.type_), [ca, toggleColumn] { toggleColumn(ca.type_); },
-                             ca.visible_, ca.type_ != static_cast<ColumnType>(ColumnTypeNavi::DIRECTORY)); //do not allow user to hide file name column!
+            menu.addCheckBox(getColumnLabel(ca.type_), [ct = ca.type_, toggleColumn] { toggleColumn(ct); },
+                             ca.visible_, ca.type_ != static_cast<ColumnType>(ColumnTypeNavi::FOLDER_NAME)); //do not allow user to hide file name column!
         }
         //--------------------------------------------------------------------------------------------------------
         menu.addSeparator();
diff --git a/FreeFileSync/Source/ui/version_check.cpp b/FreeFileSync/Source/ui/version_check.cpp
index 442caf5e..da7b0e08 100644
--- a/FreeFileSync/Source/ui/version_check.cpp
+++ b/FreeFileSync/Source/ui/version_check.cpp
@@ -17,10 +17,15 @@
 #include <wx+/http.h>
 #include <wx+/image_resources.h>
 #include "../lib/ffs_paths.h"
-#include "version_check_impl.h"
+#include "small_dlgs.h"
 
 #ifdef ZEN_WIN
     #include <zen/win_ver.h>
+    #include <ShlObj.h>
+    #include <zen/com_tools.h>
+    #include <zen/file_io.h>
+    #include <zen/long_path_prefix.h>
+    #include <zen/shell_execute.h>
 
 #elif defined ZEN_MAC
     #include <CoreServices/CoreServices.h> //Gestalt()
@@ -35,6 +40,8 @@ namespace
     const std::thread::id mainThreadId = std::this_thread::get_id();
 #endif
 
+const wchar_t ffsUpdateCheckUserAgent[] = L"FFS-Update-Check";
+
 
 std::wstring getIso639Language()
 {
@@ -43,23 +50,22 @@ std::wstring getIso639Language()
 #ifdef ZEN_WIN //use a more reliable function than wxWidgets:
     const int bufSize = 10;
     wchar_t buf[bufSize] = {};
-    int rv = ::GetLocaleInfo(LOCALE_USER_DEFAULT,    //_In_       LCID Locale,
-                             LOCALE_SISO639LANGNAME, //_In_       LCTYPE LCType,
-                             buf,                    //_Out_opt_  LPTSTR lpLCData,
-                             bufSize);               //_In_       int cchData
+    const int rv = ::GetLocaleInfo(LOCALE_USER_DEFAULT,    //_In_       LCID Locale,
+                                   LOCALE_SISO639LANGNAME, //_In_       LCTYPE LCType,
+                                   buf,                    //_Out_opt_  LPTSTR lpLCData,
+                                   bufSize);               //_In_       int cchData
     if (0 < rv && rv < bufSize)
         return buf; //MSDN: "This can be a 3-letter code for languages that don't have a 2-letter code"!
-    assert(false);
-    return std::wstring();
-
 #else
     const std::wstring localeName(wxLocale::GetLanguageCanonicalName(wxLocale::GetSystemLanguage()));
-    if (localeName.empty())
-        return std::wstring();
-
-    assert(beforeLast(localeName, L"_", IF_MISSING_RETURN_ALL).size() == 2);
-    return beforeLast(localeName, L"_", IF_MISSING_RETURN_ALL);
+    if (!localeName.empty())
+    {
+        assert(beforeLast(localeName, L"_", IF_MISSING_RETURN_ALL).size() == 2);
+        return beforeLast(localeName, L"_", IF_MISSING_RETURN_ALL);
+    }
 #endif
+    assert(false);
+    return L"zz";
 }
 
 
@@ -70,22 +76,22 @@ std::wstring getIso3166Country()
 #ifdef ZEN_WIN //use a more reliable function than wxWidgets:
     const int bufSize = 10;
     wchar_t buf[bufSize] = {};
-    int rv = ::GetLocaleInfo(LOCALE_USER_DEFAULT,     //_In_       LCID Locale,
-                             LOCALE_SISO3166CTRYNAME, //_In_       LCTYPE LCType,
-                             buf,                     //_Out_opt_  LPTSTR lpLCData,
-                             bufSize);                //_In_       int cchData
+    const int rv = ::GetLocaleInfo(LOCALE_USER_DEFAULT,     //_In_       LCID Locale,
+                                   LOCALE_SISO3166CTRYNAME, //_In_       LCTYPE LCType,
+                                   buf,                     //_Out_opt_  LPTSTR lpLCData,
+                                   bufSize);                //_In_       int cchData
     if (0 < rv && rv < bufSize)
         return buf; //MSDN: "This can also return a number, such as "029" for Caribbean."!
-    assert(false);
-    return std::wstring();
-
 #else
     const std::wstring localeName(wxLocale::GetLanguageCanonicalName(wxLocale::GetSystemLanguage()));
-    if (localeName.empty())
-        return std::wstring();
-
-    return afterLast(localeName, L"_", IF_MISSING_RETURN_NONE);
+    if (!localeName.empty())
+    {
+        if (contains(localeName, L"_"))
+            return afterLast(localeName, L"_", IF_MISSING_RETURN_NONE);
+    }
 #endif
+    assert(false);
+    return L"ZZ";
 }
 
 
@@ -95,7 +101,7 @@ std::vector<std::pair<std::string, std::string>> geHttpPostParameters()
     assert(std::this_thread::get_id() == mainThreadId); //this function is not thread-safe, e.g. consider wxWidgets usage in isPortableVersion()
     std::vector<std::pair<std::string, std::string>> params;
 
-    params.emplace_back("ffs_version", utfCvrtTo<std::string>(zen::ffsVersion));
+    params.emplace_back("ffs_version", zen::ffsVersion);
     params.emplace_back("ffs_type", isPortableVersion() ? "Portable" : "Local");
 
 #ifdef ZEN_WIN
@@ -136,53 +142,169 @@ std::vector<std::pair<std::string, std::string>> geHttpPostParameters()
 #endif
 #endif
 
-    const std::string isoLang    = utfCvrtTo<std::string>(getIso639Language());
-    const std::string isoCountry = utfCvrtTo<std::string>(getIso3166Country());
-
-    params.emplace_back("language", !isoLang   .empty() ? isoLang    : "zz");
-    params.emplace_back("country" , !isoCountry.empty() ? isoCountry : "ZZ");
+    params.emplace_back("language", utfCvrtTo<std::string>(getIso639Language()));
+    params.emplace_back("country" , utfCvrtTo<std::string>(getIso3166Country()));
 
     return params;
 }
 
 
-//access is thread-safe on Windows (WinInet), but not on Linux/OS X (wxWidgets)
-std::wstring getOnlineVersion(const std::vector<std::pair<std::string, std::string>>& postParams) //throw SysError
+#ifdef ZEN_WIN
+void runFreeFileSyncAutoUpdate(wxWindow* parent, const std::wstring& directDownloadUrl, const Zstring& fileName, std::uint64_t fileSize)
 {
-    //harmonize with wxHTTP: get_latest_version_number.php must be accessible without https!!!
-    const std::string buffer = sendHttpPost(L"http://www.freefilesync.org/get_latest_version_number.php", L"FFS-Update-Check", postParams); //throw SysError
-    const auto version = utfCvrtTo<std::wstring>(buffer);
-    return trimCpy(version);
-}
+    try
+    {
+#ifdef ZEN_WIN_VISTA_AND_LATER
+        PWSTR buf = nullptr;
+        ZEN_COM_CHECK(::SHGetKnownFolderPath(FOLDERID_Downloads,  //_In_      REFKNOWNFOLDERID rfid,
+                                             KF_FLAG_DONT_VERIFY, //_In_      DWORD dwFlags,
+                                             nullptr,             //_In_opt_  HANDLE hToken,
+                                             &buf));              //_Out_     PWSTR *ppszPath
+        ZEN_ON_SCOPE_EXIT(::CoTaskMemFree(buf));
+#else
+        wchar_t buf[MAX_PATH] = {};
+        ZEN_COM_CHECK(::SHGetFolderPath(nullptr,                      //__in   HWND hwndOwner,
+                                        CSIDL_DESKTOPDIRECTORY |
+                                        CSIDL_FLAG_DONT_VERIFY,       //__in   int nFolder,
+                                        nullptr,                      //__in   HANDLE hToken,
+                                        0 /* == SHGFP_TYPE_CURRENT*/, //__in   DWORD dwFlags,
+                                        buf));                        //__out  LPTSTR pszPath
+#endif
+        const Zstring dirPath = buf;
 
+        const Zstring installerLocalPath    = dirPath.empty() ? fileName : appendSeparator(dirPath) + fileName;
+        const Zstring installerLocalPathTmp = installerLocalPath + L".tmp";
 
-std::vector<size_t> parseVersion(const std::wstring& version)
-{
-    std::vector<size_t> output;
-    for (const std::wstring& digit : split(version, FFS_VERSION_SEPARATOR))
-        output.push_back(stringTo<size_t>(digit));
-    return output;
-}
+        if (!fileExists(installerLocalPath))
+        {
+            ZEN_ON_SCOPE_FAIL(try { removeFile(installerLocalPathTmp); }
+            catch (FileError&) {});
 
+            {
+                DownloadProgressWindow progressWin(parent, installerLocalPath, fileSize);
 
-std::wstring getOnlineChangelogDelta()
-{
-    try //harmonize with wxHTTP: get_latest_changes.php must be accessible without https!!!
+                auto notifyProgress = [&](std::int64_t bytesDelta)
+                {
+                    progressWin.notifyProgress(bytesDelta);
+                    progressWin.requestUiRefresh(); //throw DownloadProgressWindow::CancelPressed
+                };
+
+                HttpInputStream httpStreamIn = sendHttpGet(directDownloadUrl, ffsUpdateCheckUserAgent); //throw SysError
+
+                FileOutput fileStreamOut(installerLocalPathTmp, FileOutput::ACC_OVERWRITE); //throw FileError
+
+                unbufferedStreamCopy(httpStreamIn,  //throw SysError
+                                     fileStreamOut, //throw FileError
+                                     notifyProgress); //optional
+            }
+
+            //operation finished: move temp file -> this should work transactionally:
+            if (!::MoveFileEx(applyLongPathPrefix(installerLocalPathTmp).c_str(), //__in      LPCTSTR lpExistingFileName,
+                              applyLongPathPrefix(installerLocalPath   ).c_str(), //__in_opt  LPCTSTR lpNewFileName,
+                              MOVEFILE_REPLACE_EXISTING))                         //__in      DWORD dwFlags
+                THROW_LAST_FILE_ERROR(replaceCpy(replaceCpy(_("Cannot move file %x to %y."),
+                                                            L"%x", L"\n" + fmtPath(installerLocalPathTmp)),
+                                                 L"%y", L"\n" + fmtPath(installerLocalPath)), L"MoveFileEx");
+        }
+
+        const Zstring commandLine = Zstr("\"") + installerLocalPath + Zstr("\"") +
+                                    Zstr(" /silent") +
+                                    Zstr(" /dir=\"") + getInstallDirPath() + Zstr("\"") +
+                                    Zstr(" /ffs_type=") + (isPortableVersion() ? Zstr("portable") : Zstr("local")) +
+                                    Zstr(" /autoupdate");
+#ifndef NDEBUG
+        __debugbreak(); //don't mess up the dev-build running a silent install
+#endif
+        shellExecute(commandLine, ExecutionType::EXEC_TYPE_SYNC); //throw FileError
+    }
+    catch (const SysError& e)
+    {
+        showNotificationDialog(parent, DialogInfoType::ERROR2, PopupDialogCfg().setMainInstructions(_("Failed to retrieve update information.")).
+                               setDetailInstructions(e.toString()));
+    }
+    catch (const FileError& e)
     {
-        const std::string buffer = sendHttpPost(L"http://www.freefilesync.org/get_latest_changes.php", L"FFS-Update-Check", { { "since", utfCvrtTo<std::string>(zen::ffsVersion) } }); //throw SysError
-        return utfCvrtTo<std::wstring>(buffer);
+        showNotificationDialog(parent, DialogInfoType::ERROR2, PopupDialogCfg().setDetailInstructions(e.toString()));
     }
-    catch (zen::SysError&) { assert(false); return std::wstring(); }
+    catch (DownloadProgressWindow::CancelPressed&) { return; }
 }
+#endif
 
 
-void showUpdateAvailableDialog(wxWindow* parent, const std::wstring& onlineVersion, const std::wstring& onlineChangeLog)
+void showUpdateAvailableDialog(wxWindow* parent, const std::string& onlineVersion)
 {
+    std::wstring updateDetailsMsg;
+    try
+    {
+        try //harmonize with wxHTTP: get_latest_changes.php must be accessible without https!!!
+        {
+            const std::string buf = sendHttpPost(L"http://www.freefilesync.org/get_latest_changes.php", ffsUpdateCheckUserAgent,
+            { { "since", zen::ffsVersion } }).readAll(); //throw SysError
+            updateDetailsMsg = utfCvrtTo<std::wstring>(buf);
+        }
+        catch (const zen::SysError& e) { throw FileError(_("Failed to retrieve update information."), e.toString()); }
+
+#ifdef ZEN_WIN
+        Opt<DonationInfo> donationInfo = getDonationInfo(); //throw FileError
+        if (!donationInfo)
+            throw FileError(_("Automatic updates:") + L" " + _("Disabled") + L"\n(" + _("Requires FreeFileSync Donation Edition") + L")");
+
+        std::wstring directDownloadUrl;
+        Zstring installerFileName;
+        std::uint64_t installerFileSize = 0;
+        try
+        {
+            const std::string buf = sendHttpPost(L"http://www.freefilesync.org/donate/get_installer_url.php", ffsUpdateCheckUserAgent,
+                                                 xWwwFormUrlDecode(donationInfo->installerDirectDownloadUrlParamsEncoded)).readAll(); //throw SysError
+
+            //contains "download_page_url, direct_download_url, file_name, file_size" or "error"; coordinate with donate/get_installer_url.php
+            for (const std::pair<std::string, std::string>& nv : xWwwFormUrlDecode(buf))
+                if (nv.first == "direct_download_url")
+                    directDownloadUrl = utfCvrtTo<std::wstring>(nv.second);
+                else if (nv.first == "file_name")
+                    installerFileName = utfCvrtTo<Zstring>(nv.second);
+                else if (nv.first == "file_size")
+                    installerFileSize = stringTo<std::uint64_t>(nv.second);
+                else if (nv.first == "error")
+                    throw SysError(utfCvrtTo<std::wstring>(nv.second)); //e.g. expiration info
+
+            //check for empty/corrupted HTTP POST result (AV-software!)
+            if (directDownloadUrl.empty() || installerFileName.empty() || installerFileSize == 0)
+                throw SysError(L"Update server returned incomplete data.");
+        }
+        catch (const SysError& e) { throw FileError(_("Failed to retrieve update information.") + L"\n" + e.toString());  }
+
+        switch (showConfirmationDialog3(parent, DialogInfoType::INFO, PopupDialogCfg3().
+                                        setIcon(getResourceImage(L"update_available")).
+                                        setTitle(_("Check for Program Updates")).
+                                        setMainInstructions(_("A new version of FreeFileSync is available:")  + L" " + utfCvrtTo<std::wstring>(onlineVersion) + L"\n"
+                                                            + _("Auto-update now or download manually from the FreeFileSync home page?")).
+                                        setDetailInstructions(updateDetailsMsg),
+                                        _("&Auto-update"),
+                                        _("&Home page")))
+        {
+            case ConfirmationButton3::DO_IT:
+                runFreeFileSyncAutoUpdate(parent, directDownloadUrl, installerFileName, installerFileSize);
+                break;
+            case ConfirmationButton3::DONT_DO_IT:
+                openDonationEditionThankYouPage(parent);
+                break;
+            case ConfirmationButton3::CANCEL:
+                break;
+        }
+        return;
+#endif
+    }
+    catch (const FileError& e) //fall back to regular update info dialog:
+    {
+        updateDetailsMsg = e.toString() + L"\n\n" + updateDetailsMsg;
+    }
+
     switch (showConfirmationDialog(parent, DialogInfoType::INFO, PopupDialogCfg().
-                                   setIcon(getResourceImage(L"download_update")).
+                                   setIcon(getResourceImage(L"update_available")).
                                    setTitle(_("Check for Program Updates")).
-                                   setMainInstructions(_("A new version of FreeFileSync is available:")  + L" " + onlineVersion + L"\n" + _("Download now?")).
-                                   setDetailInstructions(onlineChangeLog),
+                                   setMainInstructions(_("A new version of FreeFileSync is available:")  + L" " + utfCvrtTo<std::wstring>(onlineVersion) + L"\n" + _("Download now?")).
+                                   setDetailInstructions(updateDetailsMsg),
                                    _("&Download")))
     {
         case ConfirmationButton::DO_IT:
@@ -192,13 +314,31 @@ void showUpdateAvailableDialog(wxWindow* parent, const std::wstring& onlineVersi
             break;
     }
 }
+
+
+//access is thread-safe on Windows (WinInet), but not on Linux/OS X (wxWidgets)
+std::string getOnlineVersion(const std::vector<std::pair<std::string, std::string>>& postParams) //throw SysError
+{
+    //harmonize with wxHTTP: get_latest_version_number.php must be accessible without https!!!
+    const std::string buffer = sendHttpPost(L"http://www.freefilesync.org/get_latest_version_number.php", ffsUpdateCheckUserAgent, postParams).readAll(); //throw SysError
+    return trimCpy(buffer);
+}
+
+
+std::vector<size_t> parseVersion(const std::string& version)
+{
+    std::vector<size_t> output;
+    for (const std::string& digit : split(version, FFS_VERSION_SEPARATOR))
+        output.push_back(stringTo<size_t>(digit));
+    return output;
+}
 }
 
 
-bool zen::haveNewerVersionOnline(const std::wstring& onlineVersion)
+bool zen::haveNewerVersionOnline(const std::string& onlineVersion)
 {
-    std::vector<size_t> current = parseVersion(zen::ffsVersion);
-    std::vector<size_t> online  = parseVersion(onlineVersion);
+    const std::vector<size_t> current = parseVersion(zen::ffsVersion);
+    const std::vector<size_t> online  = parseVersion(onlineVersion);
 
     if (online.empty() || online[0] == 0) //online version string may be "This website has been moved..." In this case better check for an update
         return true;
@@ -220,18 +360,18 @@ void zen::disableUpdateCheck(time_t& lastUpdateCheck)
 }
 
 
-void zen::checkForUpdateNow(wxWindow* parent, std::wstring& lastOnlineVersion, std::wstring& lastOnlineChangeLog)
+void zen::checkForUpdateNow(wxWindow* parent, std::string& lastOnlineVersion)
 {
     try
     {
-        const std::wstring onlineVersion = getOnlineVersion(geHttpPostParameters()); //throw SysError
-        lastOnlineVersion   = onlineVersion;
-        lastOnlineChangeLog = haveNewerVersionOnline(onlineVersion) ? getOnlineChangelogDelta() : L"";
+        const std::string onlineVersion = getOnlineVersion(geHttpPostParameters()); //throw SysError
+        lastOnlineVersion = onlineVersion;
 
         if (haveNewerVersionOnline(onlineVersion))
-            showUpdateAvailableDialog(parent, lastOnlineVersion, lastOnlineChangeLog);
+            showUpdateAvailableDialog(parent, lastOnlineVersion);
         else
             showNotificationDialog(parent, DialogInfoType::INFO, PopupDialogCfg().
+                                   setIcon(getResourceImage(L"update_check")).
                                    setTitle(_("Check for Program Updates")).
                                    setMainInstructions(_("FreeFileSync is up to date.")));
     }
@@ -239,8 +379,7 @@ void zen::checkForUpdateNow(wxWindow* parent, std::wstring& lastOnlineVersion, s
     {
         if (internetIsAlive())
         {
-            lastOnlineVersion = L"Unknown";
-            lastOnlineChangeLog.clear();
+            lastOnlineVersion = "Unknown";
 
             switch (showConfirmationDialog(parent, DialogInfoType::ERROR2, PopupDialogCfg().
                                            setTitle(_("Check for Program Updates")).
@@ -284,9 +423,9 @@ std::shared_ptr<UpdateCheckResultPrep> zen::periodicUpdateCheckPrepare()
 struct zen::UpdateCheckResult
 {
     UpdateCheckResult() {}
-    UpdateCheckResult(const std::wstring& ver, const Opt<zen::SysError>& err, bool alive)  : onlineVersion(ver), error(err), internetIsAlive(alive) {}
+    UpdateCheckResult(const std::string& ver, const Opt<zen::SysError>& err, bool alive)  : onlineVersion(ver), error(err), internetIsAlive(alive) {}
 
-    std::wstring onlineVersion;
+    std::string onlineVersion;
     Opt<zen::SysError> error;
     bool internetIsAlive = false;
 };
@@ -298,12 +437,12 @@ std::shared_ptr<UpdateCheckResult> zen::periodicUpdateCheckRunAsync(const Update
     try
     {
         //access is thread-safe on Windows only!
-        const std::wstring onlineVersion = getOnlineVersion(resultPrep->postParameters); //throw SysError
+        const std::string onlineVersion = getOnlineVersion(resultPrep->postParameters); //throw SysError
         return std::make_shared<UpdateCheckResult>(onlineVersion, NoValue(), true);
     }
     catch (const zen::SysError& e)
     {
-        return std::make_shared<UpdateCheckResult>(L"", e, internetIsAlive());
+        return std::make_shared<UpdateCheckResult>("", e, internetIsAlive());
     }
 #else
     return nullptr;
@@ -312,7 +451,7 @@ std::shared_ptr<UpdateCheckResult> zen::periodicUpdateCheckRunAsync(const Update
 
 
 //run on main thread:
-void zen::periodicUpdateCheckEval(wxWindow* parent, time_t& lastUpdateCheck, std::wstring& lastOnlineVersion, std::wstring& lastOnlineChangeLog, const UpdateCheckResult* resultAsync)
+void zen::periodicUpdateCheckEval(wxWindow* parent, time_t& lastUpdateCheck, std::string& lastOnlineVersion, const UpdateCheckResult* resultAsync)
 {
 #ifdef ZEN_WIN
     const UpdateCheckResult& result = *resultAsync;
@@ -332,19 +471,17 @@ void zen::periodicUpdateCheckEval(wxWindow* parent, time_t& lastUpdateCheck, std
 
     if (!result.error)
     {
-        lastUpdateCheck     = getVersionCheckCurrentTime();
-        lastOnlineVersion   = result.onlineVersion;
-        lastOnlineChangeLog = haveNewerVersionOnline(result.onlineVersion) ? getOnlineChangelogDelta() : L"";
+        lastUpdateCheck   = getVersionCheckCurrentTime();
+        lastOnlineVersion = result.onlineVersion;
 
         if (haveNewerVersionOnline(result.onlineVersion))
-            showUpdateAvailableDialog(parent, lastOnlineVersion, lastOnlineChangeLog);
+            showUpdateAvailableDialog(parent, lastOnlineVersion);
     }
     else
     {
         if (result.internetIsAlive)
         {
-            lastOnlineVersion = L"Unknown";
-            lastOnlineChangeLog.clear();
+            lastOnlineVersion = "Unknown";
 
             switch (showConfirmationDialog(parent, DialogInfoType::ERROR2, PopupDialogCfg().
                                            setTitle(_("Check for Program Updates")).
@@ -362,3 +499,21 @@ void zen::periodicUpdateCheckEval(wxWindow* parent, time_t& lastUpdateCheck, std
         //else: ignore this error
     }
 }
+
+
+#ifdef ZEN_WIN
+void zen::openDonationEditionThankYouPage(wxWindow* parent)
+{
+    try
+    {
+        if (Opt<DonationInfo> donationInfo = getDonationInfo()) //throw FileError
+            wxLaunchDefaultBrowser(donationInfo->ffsThankYouPageUrl); //don't need urlencode()
+        else
+            throw FileError(L"Corrupted installation: transaction ID not found");
+    }
+    catch (const FileError& e)
+    {
+        showNotificationDialog(parent, DialogInfoType::ERROR2, PopupDialogCfg().setDetailInstructions(e.toString()));
+    }
+}
+#endif
diff --git a/FreeFileSync/Source/ui/version_check.h b/FreeFileSync/Source/ui/version_check.h
index 01c19519..6dfe1ff9 100644
--- a/FreeFileSync/Source/ui/version_check.h
+++ b/FreeFileSync/Source/ui/version_check.h
@@ -10,14 +10,14 @@
 #include <functional>
 #include <memory>
 #include <wx/window.h>
-
+#include "version_check_impl.h"
 
 namespace zen
 {
 bool updateCheckActive (time_t  lastUpdateCheck);
 void disableUpdateCheck(time_t& lastUpdateCheck);
-bool haveNewerVersionOnline(const std::wstring& onlineVersion);
-
+bool haveNewerVersionOnline(const std::string& onlineVersion);
+//----------------------------------------------------------------------------
 //periodic update check:
 bool shouldRunPeriodicUpdateCheck(time_t lastUpdateCheck);
 
@@ -29,15 +29,15 @@ std::shared_ptr<UpdateCheckResultPrep> periodicUpdateCheckPrepare();
 //run on worker thread: (long-running part of the check)
 std::shared_ptr<UpdateCheckResult> periodicUpdateCheckRunAsync(const UpdateCheckResultPrep* resultPrep);
 //run on main thread:
-void periodicUpdateCheckEval(wxWindow* parent, time_t& lastUpdateCheck,
-                             std::wstring& lastOnlineVersion,
-                             std::wstring& lastOnlineChangeLog,
+void periodicUpdateCheckEval(wxWindow* parent, time_t& lastUpdateCheck, std::string& lastOnlineVersion,
                              const UpdateCheckResult* resultAsync);
-
 //----------------------------------------------------------------------------
-
 //call from main thread:
-void checkForUpdateNow(wxWindow* parent, std::wstring& lastOnlineVersion, std::wstring& lastOnlineChangeLog);
+void checkForUpdateNow(wxWindow* parent, std::string& lastOnlineVersion);
+//----------------------------------------------------------------------------
+#ifdef ZEN_WIN
+    void openDonationEditionThankYouPage(wxWindow* parent);
+#endif
 }
 
 #endif //VERSION_CHECK_H_324872374893274983275
diff --git a/FreeFileSync/Source/ui/version_check_impl.h b/FreeFileSync/Source/ui/version_check_impl.h
index 904da735..58412517 100644
--- a/FreeFileSync/Source/ui/version_check_impl.h
+++ b/FreeFileSync/Source/ui/version_check_impl.h
@@ -16,14 +16,14 @@ time_t getVersionCheckInactiveId()
 {
     //use current version to calculate a changing number for the inactive state near UTC begin, in order to always check for updates after installing a new version
     //=> convert version into 11-based *unique* number (this breaks lexicographical version ordering, but that's irrelevant!)
-    time_t id = 0;
-    const wchar_t* first = zen::ffsVersion;
-    const wchar_t* last = first + zen::strLength(ffsVersion);
-    std::for_each(first, last, [&](wchar_t c)
+    int id = 0;
+    const char* first = zen::ffsVersion;
+    const char* last = first + zen::strLength(ffsVersion);
+    std::for_each(first, last, [&](char c)
     {
         id *= 11;
-        if (L'0' <= c && c <= L'9')
-            id += c - L'0';
+        if ('0' <= c && c <= '9')
+            id += c - '0';
         else
         {
             assert(c == FFS_VERSION_SEPARATOR);
diff --git a/FreeFileSync/Source/version/version.h b/FreeFileSync/Source/version/version.h
index 3aefebd8..f34673b8 100644
--- a/FreeFileSync/Source/version/version.h
+++ b/FreeFileSync/Source/version/version.h
@@ -3,8 +3,8 @@
 
 namespace zen
 {
-const wchar_t ffsVersion[] = L"8.6"; //internal linkage!
-const wchar_t FFS_VERSION_SEPARATOR = L'.';
+const char ffsVersion[] = "8.7"; //internal linkage!
+const char FFS_VERSION_SEPARATOR = '.';
 }
 
 #endif
diff --git a/wx+/async_task.h b/wx+/async_task.h
index 915f9602..7ac03949 100644
--- a/wx+/async_task.h
+++ b/wx+/async_task.h
@@ -24,6 +24,9 @@ Run a task in an async thread, but process result in GUI event loop
 
 2. schedule async task and synchronous continuation:
     guiQueue.processAsync(evalAsync, evalOnGui);
+
+Alternative: use wxWidgets' inter-thread communication (wxEvtHandler::QueueEvent) https://wiki.wxwidgets.org/Inter-Thread_and_Inter-Process_communication
+        => don't bother, probably too many MT race conditions lurking around
 */
 
 namespace impl
@@ -74,7 +77,7 @@ public:
     void add(Fun&& evalAsync, Fun2&& evalOnGui)
     {
         using ResultType = decltype(evalAsync());
-        tasks.push_back(std::make_unique<ConcreteTask<ResultType, Fun2>>(zen::runAsync(std::forward<Fun>(evalAsync)), std::forward<Fun2>(evalOnGui)));
+        tasks_.push_back(std::make_unique<ConcreteTask<ResultType, Fun2>>(zen::runAsync(std::forward<Fun>(evalAsync)), std::forward<Fun2>(evalOnGui)));
     }
     //equivalent to "evalOnGui(evalAsync())"
     //  -> evalAsync: the usual thread-safety requirements apply!
@@ -82,14 +85,14 @@ public:
 
     void evalResults() //call from gui thread repreatedly
     {
-        if (!inRecursion) //prevent implicit recursion, e.g. if we're called from an idle event and spawn another one within the callback below
+        if (!inRecursion_) //prevent implicit recursion, e.g. if we're called from an idle event and spawn another one within the callback below
         {
-            inRecursion = true;
-            ZEN_ON_SCOPE_EXIT(inRecursion = false);
+            inRecursion_ = true;
+            ZEN_ON_SCOPE_EXIT(inRecursion_ = false);
 
             std::vector<std::unique_ptr<Task>> readyTasks; //Reentrancy; access to AsyncTasks::add is not protected! => evaluate outside erase_if
 
-            erase_if(tasks, [&](std::unique_ptr<Task>& task)
+            erase_if(tasks_, [&](std::unique_ptr<Task>& task)
             {
                 if (task->resultReady())
                 {
@@ -104,14 +107,14 @@ public:
         }
     }
 
-    bool empty() const { return tasks.empty(); }
+    bool empty() const { return tasks_.empty(); }
 
 private:
     AsyncTasks           (const AsyncTasks&) = delete;
     AsyncTasks& operator=(const AsyncTasks&) = delete;
 
-    bool inRecursion = false;
-    std::vector<std::unique_ptr<Task>> tasks;
+    bool inRecursion_ = false;
+    std::vector<std::unique_ptr<Task>> tasks_;
 };
 }
 
@@ -119,27 +122,27 @@ private:
 class AsyncGuiQueue : private wxEvtHandler
 {
 public:
-    AsyncGuiQueue() { timer.Connect(wxEVT_TIMER, wxEventHandler(AsyncGuiQueue::onTimerEvent), nullptr, this); }
+    AsyncGuiQueue() { timer_.Connect(wxEVT_TIMER, wxEventHandler(AsyncGuiQueue::onTimerEvent), nullptr, this); }
 
     template <class Fun, class Fun2>
     void processAsync(Fun&& evalAsync, Fun2&& evalOnGui)
     {
-        asyncTasks.add(std::forward<Fun >(evalAsync),
-                       std::forward<Fun2>(evalOnGui));
-        if (!timer.IsRunning())
-            timer.Start(50 /*unit: [ms]*/);
+        asyncTasks_.add(std::forward<Fun >(evalAsync),
+                        std::forward<Fun2>(evalOnGui));
+        if (!timer_.IsRunning())
+            timer_.Start(50 /*unit: [ms]*/);
     }
 
 private:
     void onTimerEvent(wxEvent& event) //schedule and run long-running tasks asynchronously
     {
-        asyncTasks.evalResults(); //process results on GUI queue
-        if (asyncTasks.empty())
-            timer.Stop();
+        asyncTasks_.evalResults(); //process results on GUI queue
+        if (asyncTasks_.empty())
+            timer_.Stop();
     }
 
-    impl::AsyncTasks asyncTasks;
-    wxTimer timer; //don't use wxWidgets' idle handling => repeated idle requests/consumption hogs 100% cpu!
+    impl::AsyncTasks asyncTasks_;
+    wxTimer timer_; //don't use wxWidgets' idle handling => repeated idle requests/consumption hogs 100% cpu!
 };
 
 }
diff --git a/wx+/file_drop.h b/wx+/file_drop.h
index c3ffe09c..57880ce2 100644
--- a/wx+/file_drop.h
+++ b/wx+/file_drop.h
@@ -134,6 +134,13 @@ public:
 private:
     bool OnDropFiles(wxCoord x, wxCoord y, const wxArrayString& fileArray) override
     {
+        /*Linux, MTP: we get an empty file array
+            => switching to wxTextDropTarget won't help (much): we'd get the format
+                mtp://[usb:001,002]/Telefonspeicher/Folder/file.txt
+            instead of
+                /run/user/1000/gvfs/mtp:host=%5Busb%3A001%2C002%5D/Telefonspeicher/Folder/file.txt
+        */
+
         //wxPoint clientDropPos(x, y)
         std::vector<Zstring> filePaths;
         for (const wxString& file : fileArray)
diff --git a/wx+/grid.cpp b/wx+/grid.cpp
index 13c06704..5d393f08 100644
--- a/wx+/grid.cpp
+++ b/wx+/grid.cpp
@@ -359,8 +359,18 @@ private:
 
     void onPaintEvent(wxPaintEvent& event)
     {
+#ifndef NDEBUG
+#ifdef ZEN_WIN
+        if (runningPaintEvent_ == true) //looks like showing the assert window here would quit the debug session
+            __debugbreak();
+#else
+        assert(runningPaintEvent_ == false); //catch unexpected recursion, e.g.: getIconByIndex() seems to run a message loop in rare cases!
+#endif
+        runningPaintEvent_ = true;
+        ZEN_ON_SCOPE_EXIT(runningPaintEvent_ = false);
+#endif
         //wxAutoBufferedPaintDC dc(this); -> this one happily fucks up for RTL layout by not drawing the first column (x = 0)!
-        BufferedPaintDC dc(*this, doubleBuffer);
+        BufferedPaintDC dc(*this, doubleBuffer_);
 
         assert(GetSize() == GetClientSize());
 
@@ -378,7 +388,10 @@ private:
     void onEraseBackGround(wxEraseEvent& event) {}
 
     Grid& parent_;
-    Opt<wxBitmap> doubleBuffer;
+    Opt<wxBitmap> doubleBuffer_;
+#ifndef NDEBUG
+    bool runningPaintEvent_ = false;
+#endif
 };
 
 //----------------------------------------------------------------------------------------------------------------
@@ -427,7 +440,7 @@ class Grid::RowLabelWin : public SubWindow
 public:
     RowLabelWin(Grid& parent) :
         SubWindow(parent),
-        rowHeight(parent.GetCharHeight() + 2 + 1) {} //default height; don't call any functions on "parent" other than those from wxWindow during construction!
+        rowHeight_(parent.GetCharHeight() + 2 + 1) {} //default height; don't call any functions on "parent" other than those from wxWindow during construction!
     //2 for some more space, 1 for bottom border (gives 15 + 2 + 1 on Windows, 17 + 2 + 1 on Ubuntu)
 
     int getBestWidth(ptrdiff_t rowFrom, ptrdiff_t rowTo)
@@ -444,27 +457,27 @@ public:
         return bestWidth;
     }
 
-    size_t getLogicalHeight() const { return refParent().getRowCount() * rowHeight; }
+    size_t getLogicalHeight() const { return refParent().getRowCount() * rowHeight_; }
 
     ptrdiff_t getRowAtPos(ptrdiff_t posY) const //returns < 0 on invalid input, else row number within: [0, rowCount]; rowCount if out of range
     {
-        if (posY >= 0 && rowHeight > 0)
+        if (posY >= 0 && rowHeight_ > 0)
         {
-            const size_t row = posY / rowHeight;
+            const size_t row = posY / rowHeight_;
             return std::min(row, refParent().getRowCount());
         }
         return -1;
     }
 
-    int getRowHeight() const { return rowHeight; } //guarantees to return size >= 1 !
-    void setRowHeight(int height) { assert(height > 0); rowHeight = std::max(1, height); }
+    int getRowHeight() const { return rowHeight_; } //guarantees to return size >= 1 !
+    void setRowHeight(int height) { assert(height > 0); rowHeight_ = std::max(1, height); }
 
     wxRect getRowLabelArea(size_t row) const //returns empty rect if row not found
     {
         assert(GetClientAreaOrigin() == wxPoint());
         if (row < refParent().getRowCount())
-            return wxRect(wxPoint(0, rowHeight * row),
-                          wxSize(GetClientSize().GetWidth(), rowHeight));
+            return wxRect(wxPoint(0, rowHeight_ * row),
+                          wxSize(GetClientSize().GetWidth(), rowHeight_));
         return wxRect();
     }
 
@@ -473,8 +486,8 @@ public:
         const int yFrom = refParent().CalcUnscrolledPosition(clientRect.GetTopLeft    ()).y;
         const int yTo   = refParent().CalcUnscrolledPosition(clientRect.GetBottomRight()).y;
 
-        return std::make_pair(std::max(yFrom / rowHeight, 0),
-                              std::min<ptrdiff_t>((yTo  / rowHeight) + 1, refParent().getRowCount()));
+        return std::make_pair(std::max(yFrom / rowHeight_, 0),
+                              std::min<ptrdiff_t>((yTo  / rowHeight_) + 1, refParent().getRowCount()));
     }
 
 private:
@@ -552,7 +565,7 @@ private:
     void onMouseMovement(wxMouseEvent& event) override { refParent().redirectRowLabelEvent(event); }
     void onMouseLeftUp  (wxMouseEvent& event) override { refParent().redirectRowLabelEvent(event); }
 
-    int rowHeight;
+    int rowHeight_;
 };
 
 
@@ -670,21 +683,21 @@ private:
     {
         if (auto dataView = refParent().getDataProvider())
         {
-            const bool isHighlighted = activeResizing    ? col == activeResizing   ->getColumn    () : //highlight column on mouse-over
-                                       activeClickOrMove ? col == activeClickOrMove->getColumnFrom() :
-                                       highlightCol      ? col == *highlightCol                      :
+            const bool isHighlighted = activeResizing_    ? col == activeResizing_   ->getColumn    () : //highlight_ column on mouse-over
+                                       activeClickOrMove_ ? col == activeClickOrMove_->getColumnFrom() :
+                                       highlightCol_      ? col == *highlightCol_                      :
                                        false;
 
             RecursiveDcClipper clip(dc, rect);
             dataView->renderColumnLabel(refParent(), dc, rect, colType, isHighlighted);
 
             //draw move target location
-            if (refParent().allowColumnMove)
-                if (activeClickOrMove && activeClickOrMove->isRealMove())
+            if (refParent().allowColumnMove_)
+                if (activeClickOrMove_ && activeClickOrMove_->isRealMove())
                 {
-                    if (col + 1 == activeClickOrMove->refColumnTo()) //handle pos 1, 2, .. up to "at end" position
+                    if (col + 1 == activeClickOrMove_->refColumnTo()) //handle pos 1, 2, .. up to "at end" position
                         dc.GradientFillLinear(wxRect(rect.GetTopRight(), rect.GetBottomRight() + wxPoint(-2, 0)), getColorLabelGradientFrom(), *wxBLUE, wxSOUTH);
-                    else if (col == activeClickOrMove->refColumnTo() && col == 0) //pos 0
+                    else if (col == activeClickOrMove_->refColumnTo() && col == 0) //pos 0
                         dc.GradientFillLinear(wxRect(rect.GetTopLeft(), rect.GetBottomLeft() + wxPoint(2, 0)), getColorLabelGradientFrom(), *wxBLUE, wxSOUTH);
                 }
         }
@@ -695,8 +708,8 @@ private:
         if (FindFocus() != &refParent().getMainWin())
             refParent().getMainWin().SetFocus();
 
-        activeResizing.reset();
-        activeClickOrMove.reset();
+        activeResizing_.reset();
+        activeClickOrMove_.reset();
 
         if (Opt<ColAction> action = refParent().clientPosToColumnAction(event.GetPosition()))
         {
@@ -704,26 +717,26 @@ private:
             {
                 if (!event.LeftDClick()) //double-clicks never seem to arrive here; why is this checked at all???
                     if (Opt<int> colWidth = refParent().getColWidth(action->col))
-                        activeResizing = std::make_unique<ColumnResizing>(*this, action->col, *colWidth, event.GetPosition().x);
+                        activeResizing_ = std::make_unique<ColumnResizing>(*this, action->col, *colWidth, event.GetPosition().x);
             }
             else //a move or single click
-                activeClickOrMove = std::make_unique<ColumnMove>(*this, action->col, event.GetPosition().x);
+                activeClickOrMove_ = std::make_unique<ColumnMove>(*this, action->col, event.GetPosition().x);
         }
         event.Skip();
     }
 
     void onMouseLeftUp(wxMouseEvent& event) override
     {
-        activeResizing.reset(); //nothing else to do, actual work done by onMouseMovement()
+        activeResizing_.reset(); //nothing else to do, actual work done by onMouseMovement()
 
-        if (activeClickOrMove)
+        if (activeClickOrMove_)
         {
-            if (activeClickOrMove->isRealMove())
+            if (activeClickOrMove_->isRealMove())
             {
-                if (refParent().allowColumnMove)
+                if (refParent().allowColumnMove_)
                 {
-                    const size_t colFrom = activeClickOrMove->getColumnFrom();
-                    size_t       colTo   = activeClickOrMove->refColumnTo();
+                    const size_t colFrom = activeClickOrMove_->getColumnFrom();
+                    size_t       colTo   = activeClickOrMove_->refColumnTo();
 
                     if (colTo > colFrom) //simulate "colFrom" deletion
                         --colTo;
@@ -733,10 +746,10 @@ private:
             }
             else //notify single label click
             {
-                if (const Opt<ColumnType> colType = refParent().colToType(activeClickOrMove->getColumnFrom()))
+                if (const Opt<ColumnType> colType = refParent().colToType(activeClickOrMove_->getColumnFrom()))
                     sendEventNow(GridLabelClickEvent(EVENT_GRID_COL_LABEL_MOUSE_LEFT, event, *colType));
             }
-            activeClickOrMove.reset();
+            activeClickOrMove_.reset();
         }
 
         refParent().updateWindowSizes(); //looks strange if done during onMouseMovement()
@@ -746,8 +759,8 @@ private:
 
     void onMouseCaptureLost(wxMouseCaptureLostEvent& event) override
     {
-        activeResizing.reset();
-        activeClickOrMove.reset();
+        activeResizing_.reset();
+        activeClickOrMove_.reset();
         Refresh();
         //event.Skip(); -> we DID handle it!
     }
@@ -770,10 +783,10 @@ private:
 
     void onMouseMovement(wxMouseEvent& event) override
     {
-        if (activeResizing)
+        if (activeResizing_)
         {
-            const auto col     = activeResizing->getColumn();
-            const int newWidth = activeResizing->getStartWidth() + event.GetPosition().x - activeResizing->getStartPosX();
+            const auto col     = activeResizing_->getColumn();
+            const int newWidth = activeResizing_->getStartWidth() + event.GetPosition().x - activeResizing_->getStartPosX();
 
             //set width tentatively
             refParent().setColumnWidth(newWidth, col, ALLOW_GRID_EVENT);
@@ -785,23 +798,23 @@ private:
 
             refParent().Refresh(); //refresh columns on main grid as well!
         }
-        else if (activeClickOrMove)
+        else if (activeClickOrMove_)
         {
             const int clientPosX = event.GetPosition().x;
-            if (std::abs(clientPosX - activeClickOrMove->getStartPosX()) > COLUMN_MOVE_DELAY) //real move (not a single click)
+            if (std::abs(clientPosX - activeClickOrMove_->getStartPosX()) > COLUMN_MOVE_DELAY) //real move (not a single click)
             {
-                activeClickOrMove->setRealMove();
+                activeClickOrMove_->setRealMove();
 
                 const ptrdiff_t col = refParent().clientPosToMoveTargetColumn(event.GetPosition());
                 if (col >= 0)
-                    activeClickOrMove->refColumnTo() = col;
+                    activeClickOrMove_->refColumnTo() = col;
             }
         }
         else
         {
             if (const Opt<ColAction> action = refParent().clientPosToColumnAction(event.GetPosition()))
             {
-                highlightCol = action->col;
+                highlightCol_ = action->col;
 
                 if (action->wantResize)
                     SetCursor(wxCURSOR_SIZEWE); //set window-local only! :)
@@ -810,7 +823,7 @@ private:
             }
             else
             {
-                highlightCol = NoValue();
+                highlightCol_ = NoValue();
                 SetCursor(*wxSTANDARD_CURSOR);
             }
         }
@@ -832,7 +845,7 @@ private:
 
     void onLeaveWindow(wxMouseEvent& event) override
     {
-        highlightCol = NoValue(); //wxEVT_LEAVE_WINDOW does not respect mouse capture! -> however highlight is drawn unconditionally during move/resize!
+        highlightCol_ = NoValue(); //wxEVT_LEAVE_WINDOW does not respect mouse capture! -> however highlight_ is drawn unconditionally during move/resize!
         Refresh();
         event.Skip();
     }
@@ -853,9 +866,9 @@ private:
         event.Skip();
     }
 
-    std::unique_ptr<ColumnResizing> activeResizing;
-    std::unique_ptr<ColumnMove>     activeClickOrMove;
-    Opt<size_t>                     highlightCol; //column during mouse-over
+    std::unique_ptr<ColumnResizing> activeResizing_;
+    std::unique_ptr<ColumnMove>     activeClickOrMove_;
+    Opt<size_t>                     highlightCol_; //column during mouse-over
 };
 
 //----------------------------------------------------------------------------------------------------------------
@@ -877,16 +890,16 @@ public:
         Connect(EVENT_GRID_HAS_SCROLLED, wxEventHandler(MainWin::onRequestWindowUpdate), nullptr, this);
     }
 
-    ~MainWin() { assert(!gridUpdatePending); }
+    ~MainWin() { assert(!gridUpdatePending_); }
 
-    size_t getCursor() const { return cursorRow; }
-    size_t getAnchor() const { return selectionAnchor; }
+    size_t getCursor() const { return cursorRow_; }
+    size_t getAnchor() const { return selectionAnchor_; }
 
     void setCursor(size_t newCursorRow, size_t newAnchorRow)
     {
-        cursorRow       = newCursorRow;
-        selectionAnchor = newAnchorRow;
-        activeSelection.reset(); //e.g. user might search with F3 while holding down left mouse button
+        cursorRow_       = newCursorRow;
+        selectionAnchor_ = newAnchorRow;
+        activeSelection_.reset(); //e.g. user might search with F3 while holding down left mouse button
     }
 
 private:
@@ -948,25 +961,25 @@ private:
 
     HoverArea getRowHoverToDraw(ptrdiff_t row) const
     {
-        if (activeSelection)
+        if (activeSelection_)
         {
-            if (activeSelection->getFirstClick().row_ == row)
-                return activeSelection->getFirstClick().hoverArea_;
+            if (activeSelection_->getFirstClick().row_ == row)
+                return activeSelection_->getFirstClick().hoverArea_;
         }
-        else if (highlight.row == row)
-            return highlight.rowHover;
+        else if (highlight_.row == row)
+            return highlight_.rowHover;
         return HoverArea::NONE;
     }
 
     bool drawAsSelected(size_t row) const
     {
-        if (activeSelection) //check if user is currently selecting with mouse
+        if (activeSelection_) //check if user is currently selecting with mouse
         {
-            const size_t rowFrom = std::min(activeSelection->getStartRow(), activeSelection->getCurrentRow());
-            const size_t rowTo   = std::max(activeSelection->getStartRow(), activeSelection->getCurrentRow());
+            const size_t rowFrom = std::min(activeSelection_->getStartRow(), activeSelection_->getCurrentRow());
+            const size_t rowTo   = std::max(activeSelection_->getStartRow(), activeSelection_->getCurrentRow());
 
             if (rowFrom <= row && row <= rowTo)
-                return activeSelection->isPositiveSelect(); //overwrite default
+                return activeSelection_->isPositiveSelect(); //overwrite default
         }
         return refParent().isSelected(row);
     }
@@ -1009,15 +1022,15 @@ private:
                 if (!event.RightDown() || !refParent().isSelected(row)) //do NOT start a new selection if user right-clicks on a selected area!
                 {
                     if (event.ControlDown())
-                        activeSelection = std::make_unique<MouseSelection>(*this, row, !refParent().isSelected(row), mouseEvent);
+                        activeSelection_ = std::make_unique<MouseSelection>(*this, row, !refParent().isSelected(row), mouseEvent);
                     else if (event.ShiftDown())
                     {
-                        activeSelection = std::make_unique<MouseSelection>(*this, selectionAnchor, true, mouseEvent);
+                        activeSelection_ = std::make_unique<MouseSelection>(*this, selectionAnchor_, true, mouseEvent);
                         refParent().clearSelection(ALLOW_GRID_EVENT);
                     }
                     else
                     {
-                        activeSelection = std::make_unique<MouseSelection>(*this, row, true, mouseEvent);
+                        activeSelection_ = std::make_unique<MouseSelection>(*this, row, true, mouseEvent);
                         refParent().clearSelection(ALLOW_GRID_EVENT);
                     }
                 }
@@ -1032,31 +1045,31 @@ private:
 
     void onMouseUp(wxMouseEvent& event)
     {
-        if (activeSelection)
+        if (activeSelection_)
         {
             const size_t rowCount = refParent().getRowCount();
             if (rowCount > 0)
             {
-                if (activeSelection->getCurrentRow() < rowCount)
+                if (activeSelection_->getCurrentRow() < rowCount)
                 {
-                    cursorRow = activeSelection->getCurrentRow();
-                    selectionAnchor = activeSelection->getStartRow(); //allowed to be "out of range"
+                    cursorRow_ = activeSelection_->getCurrentRow();
+                    selectionAnchor_ = activeSelection_->getStartRow(); //allowed to be "out of range"
                 }
-                else if (activeSelection->getStartRow() < rowCount) //don't change cursor if "to" and "from" are out of range
+                else if (activeSelection_->getStartRow() < rowCount) //don't change cursor if "to" and "from" are out of range
                 {
-                    cursorRow = rowCount - 1;
-                    selectionAnchor = activeSelection->getStartRow(); //allowed to be "out of range"
+                    cursorRow_ = rowCount - 1;
+                    selectionAnchor_ = activeSelection_->getStartRow(); //allowed to be "out of range"
                 }
                 else //total selection "out of range"
-                    selectionAnchor = cursorRow;
+                    selectionAnchor_ = cursorRow_;
             }
             //slight deviation from Explorer: change cursor while dragging mouse! -> unify behavior with shift + direction keys
 
-            refParent().selectRangeAndNotify(activeSelection->getStartRow  (), //from
-                                             activeSelection->getCurrentRow(), //to
-                                             activeSelection->isPositiveSelect(),
-                                             &activeSelection->getFirstClick());
-            activeSelection.reset();
+            refParent().selectRangeAndNotify(activeSelection_->getStartRow  (), //from
+                                             activeSelection_->getCurrentRow(), //to
+                                             activeSelection_->isPositiveSelect(),
+                                             &activeSelection_->getFirstClick());
+            activeSelection_.reset();
         }
 
         if (auto prov = refParent().getDataProvider())
@@ -1070,7 +1083,7 @@ private:
             sendEventNow(GridClickEvent(event.RightUp() ? EVENT_GRID_MOUSE_RIGHT_UP : EVENT_GRID_MOUSE_LEFT_UP, event, row, rowHover));
         }
 
-        //update highlight and tooltip: on OS X no mouse movement event is generated after a mouse button click (unlike on Windows)
+        //update highlight_ and tooltip: on OS X no mouse movement event is generated after a mouse button click (unlike on Windows)
         event.SetPosition(ScreenToClient(wxGetMousePosition())); //mouse position may have changed within above callbacks (e.g. context menu was shown)!
         onMouseMovement(event);
 
@@ -1080,8 +1093,8 @@ private:
 
     void onMouseCaptureLost(wxMouseCaptureLostEvent& event) override
     {
-        activeSelection.reset();
-        highlight.row = -1;
+        activeSelection_.reset();
+        highlight_.row = -1;
         Refresh();
         //event.Skip(); -> we DID handle it!
     }
@@ -1104,14 +1117,14 @@ private:
             }();
             setToolTip(toolTip); //show even during mouse selection!
 
-            if (activeSelection)
-                activeSelection->evalMousePos(); //call on both mouse movement + timer event!
+            if (activeSelection_)
+                activeSelection_->evalMousePos(); //call on both mouse movement + timer event!
             else
             {
-                refreshHighlight(highlight);
-                highlight.row      = row;
-                highlight.rowHover = rowHover;
-                refreshHighlight(highlight); //multiple Refresh() calls are condensed into single one!
+                refreshHighlight(highlight_);
+                highlight_.row      = row;
+                highlight_.rowHover = rowHover;
+                refreshHighlight(highlight_); //multiple Refresh() calls are condensed into single one!
             }
         }
         event.Skip();
@@ -1119,10 +1132,10 @@ private:
 
     void onLeaveWindow(wxMouseEvent& event) override //wxEVT_LEAVE_WINDOW does not respect mouse capture!
     {
-        if (!activeSelection)
+        if (!activeSelection_)
         {
-            refreshHighlight(highlight);
-            highlight.row = -1;
+            refreshHighlight(highlight_);
+            highlight_.row = -1;
         }
 
         event.Skip();
@@ -1138,8 +1151,8 @@ private:
             wnd_(wnd), rowStart_(rowStart), rowCurrent_(rowStart), positiveSelect_(positiveSelect), firstClick_(firstClick)
         {
             wnd_.CaptureMouse();
-            timer.Connect(wxEVT_TIMER, wxEventHandler(MouseSelection::onTimer), nullptr, this);
-            timer.Start(100); //timer interval in ms
+            timer_.Connect(wxEVT_TIMER, wxEventHandler(MouseSelection::onTimer), nullptr, this);
+            timer_.Start(100); //timer interval in ms
             evalMousePos();
         }
         ~MouseSelection() { if (wnd_.HasCapture()) wnd_.ReleaseMouse(); }
@@ -1152,8 +1165,8 @@ private:
         void evalMousePos()
         {
             const auto now = std::chrono::steady_clock::now();
-            const double deltaSecs = std::chrono::duration<double>(now - lastEvalTime).count(); //unit: [sec]
-            lastEvalTime = now;
+            const double deltaSecs = std::chrono::duration<double>(now - lastEvalTime_).count(); //unit: [sec]
+            lastEvalTime_ = now;
 
             const wxPoint clientPos = wnd_.ScreenToClient(wxGetMousePosition());
             const wxSize clientSize = wnd_.GetClientSize();
@@ -1182,14 +1195,14 @@ private:
                     toScroll = 0;
             };
 
-            autoScroll(overlapPixX, toScrollX);
-            autoScroll(overlapPixY, toScrollY);
+            autoScroll(overlapPixX, toScrollX_);
+            autoScroll(overlapPixY, toScrollY_);
 
-            if (static_cast<int>(toScrollX) != 0 || static_cast<int>(toScrollY) != 0)
+            if (static_cast<int>(toScrollX_) != 0 || static_cast<int>(toScrollY_) != 0)
             {
-                wnd_.refParent().scrollDelta(static_cast<int>(toScrollX), static_cast<int>(toScrollY)); //
-                toScrollX -= static_cast<int>(toScrollX); //rounds down for positive numbers, up for negative,
-                toScrollY -= static_cast<int>(toScrollY); //exactly what we want
+                wnd_.refParent().scrollDelta(static_cast<int>(toScrollX_), static_cast<int>(toScrollY_)); //
+                toScrollX_ -= static_cast<int>(toScrollX_); //rounds down for positive numbers, up for negative,
+                toScrollY_ -= static_cast<int>(toScrollY_); //exactly what we want
             }
 
             //select current row *after* scrolling
@@ -1214,10 +1227,10 @@ private:
         ptrdiff_t rowCurrent_;
         const bool positiveSelect_;
         const GridClickEvent firstClick_;
-        wxTimer timer;
-        double toScrollX = 0; //count outstanding scroll unit fractions while dragging mouse
-        double toScrollY = 0; //
-        std::chrono::steady_clock::time_point lastEvalTime = std::chrono::steady_clock::now();
+        wxTimer timer_;
+        double toScrollX_ = 0; //count outstanding scroll unit fractions while dragging mouse
+        double toScrollY_ = 0; //
+        std::chrono::steady_clock::time_point lastEvalTime_ = std::chrono::steady_clock::now();
     };
 
     struct MouseHighlight
@@ -1236,12 +1249,12 @@ private:
         //which *first* calls us, MainWin::ScrollWindow(), and *then* internally updates m_yScrollPosition
         //=> we cannot use CalcUnscrolledPosition() here which gives the wrong/outdated value!!!
         //=> we need to update asynchronously:
-        //=> don't use plain async event => severe performance issues on wxGTK!
+        //=> don't send async event repeatedly => severe performance issues on wxGTK!
         //=> can't use idle event neither: too few idle events on Windows, e.g. NO idle events while mouse drag-scrolling!
         //=> solution: send single async event at most!
-        if (!gridUpdatePending) //without guarding, the number of outstanding async events can become very high during scrolling!! test case: Ubuntu: 170; Windows: 20
+        if (!gridUpdatePending_) //without guarding, the number of outstanding async events can become very high during scrolling!! test case: Ubuntu: 170; Windows: 20
         {
-            gridUpdatePending = true;
+            gridUpdatePending_ = true;
             wxCommandEvent scrollEvent(EVENT_GRID_HAS_SCROLLED);
             AddPendingEvent(scrollEvent); //asynchronously call updateAfterScroll()
         }
@@ -1249,8 +1262,8 @@ private:
 
     void onRequestWindowUpdate(wxEvent& event)
     {
-        assert(gridUpdatePending);
-        ZEN_ON_SCOPE_EXIT(gridUpdatePending = false);
+        assert(gridUpdatePending_);
+        ZEN_ON_SCOPE_EXIT(gridUpdatePending_ = false);
 
         refParent().updateWindowSizes(false); //row label width has changed -> do *not* update scrollbars: recursion on wxGTK! -> still a problem, now that we're called async??
         rowLabelWin_.Update(); //update while dragging scroll thumb
@@ -1267,19 +1280,19 @@ private:
     void refreshHighlight(const MouseHighlight& hl)
     {
         const ptrdiff_t rowCount = refParent().getRowCount();
-        if (0 <= hl.row && hl.row < rowCount && hl.rowHover != HoverArea::NONE) //no highlight? => NOP!
+        if (0 <= hl.row && hl.row < rowCount && hl.rowHover != HoverArea::NONE) //no highlight_? => NOP!
             refreshRow(hl.row);
     }
 
     RowLabelWin& rowLabelWin_;
     ColLabelWin& colLabelWin_;
 
-    std::unique_ptr<MouseSelection> activeSelection; //bound while user is selecting with mouse
-    MouseHighlight highlight; //current mouse highlight (superseeded by activeSelection if available)
+    std::unique_ptr<MouseSelection> activeSelection_; //bound while user is selecting with mouse
+    MouseHighlight highlight_; //current mouse highlight_ (superseeded by activeSelection_ if available)
 
-    ptrdiff_t cursorRow = 0;
-    size_t selectionAnchor = 0;
-    bool gridUpdatePending = false;
+    ptrdiff_t cursorRow_ = 0;
+    size_t selectionAnchor_ = 0;
+    bool gridUpdatePending_ = false;
 };
 
 //----------------------------------------------------------------------------------------------------------------
@@ -1353,7 +1366,7 @@ void Grid::updateWindowSizes(bool updateScrollbar)
     const ptrdiff_t logicalHeight = rowLabelWin_->getLogicalHeight();                   //
 
     int rowLabelWidth = 0;
-    if (drawRowLabel && logicalHeight > 0)
+    if (drawRowLabel_ && logicalHeight > 0)
     {
         ptrdiff_t yFrom = CalcUnscrolledPosition(wxPoint(0, 0)).y;
         ptrdiff_t yTo   = CalcUnscrolledPosition(wxPoint(0, mainWinHeightGross - 1)).y ;
@@ -1406,8 +1419,8 @@ void Grid::updateWindowSizes(bool updateScrollbar)
         if (logicalHeight <= mainWinHeightGross &&
             getColWidthsSum(mainWinWidthGross) <= mainWinWidthGross &&
             //this special case needs to be considered *only* when both scrollbars are flexible:
-            showScrollbarX == SB_SHOW_AUTOMATIC &&
-            showScrollbarY == SB_SHOW_AUTOMATIC)
+            showScrollbarX_ == SB_SHOW_AUTOMATIC &&
+            showScrollbarY_ == SB_SHOW_AUTOMATIC)
             setScrollbars2(0, 0); //no scrollbars required at all! -> wxScrolledWindow requires active help to detect this special case!
         else
         {
@@ -1461,7 +1474,7 @@ wxSize Grid::GetSizeAvailableForScrollTarget(const wxSize& size)
     const ptrdiff_t logicalHeight = rowLabelWin_->getLogicalHeight();              //
 
     int rowLabelWidth = 0;
-    if (drawRowLabel && logicalHeight > 0)
+    if (drawRowLabel_ && logicalHeight > 0)
     {
         ptrdiff_t yFrom = CalcUnscrolledPosition(wxPoint(0, 0)).y;
         ptrdiff_t yTo   = CalcUnscrolledPosition(wxPoint(0, mainWinHeightGross - 1)).y ;
@@ -1624,14 +1637,14 @@ void Grid::setColumnLabelHeight(int height)
 
 void Grid::showRowLabel(bool show)
 {
-    drawRowLabel = show;
+    drawRowLabel_ = show;
     updateWindowSizes();
 }
 
 
 void Grid::selectAllRows(GridEventPolicy rangeEventPolicy)
 {
-    selection.selectAll();
+    selection_.selectAll();
     mainWin_->Refresh();
 
     if (rangeEventPolicy == ALLOW_GRID_EVENT) //notify event, even if we're not triggered by user interaction
@@ -1645,7 +1658,7 @@ void Grid::selectAllRows(GridEventPolicy rangeEventPolicy)
 
 void Grid::clearSelection(GridEventPolicy rangeEventPolicy)
 {
-    selection.clear();
+    selection_.clear();
     mainWin_->Refresh();
 
     if (rangeEventPolicy == ALLOW_GRID_EVENT) //notify event, even if we're not triggered by user interaction
@@ -1694,14 +1707,14 @@ size_t Grid::getRowCount() const
 void Grid::Refresh(bool eraseBackground, const wxRect* rect)
 {
     const size_t rowCountNew = getRowCount();
-    if (rowCountOld != rowCountNew)
+    if (rowCountOld_ != rowCountNew)
     {
-        rowCountOld = rowCountNew;
+        rowCountOld_ = rowCountNew;
         updateWindowSizes();
     }
 
-    if (selection.maxSize() != rowCountNew) //clear selection only when needed (consider setSelectedRows())
-        selection.init(rowCountNew);
+    if (selection_.maxSize() != rowCountNew) //clear selection only when needed (consider setSelectedRows())
+        selection_.init(rowCountNew);
 
     wxScrolledWindow::Refresh(eraseBackground, rect);
 }
@@ -1718,7 +1731,7 @@ void Grid::setRowHeight(int height)
 void Grid::setColumnConfig(const std::vector<Grid::ColumnAttribute>& attr)
 {
     //hold ownership of non-visible columns
-    oldColAttributes = attr;
+    oldColAttributes_ = attr;
 
     std::vector<VisibleColumn> visCols;
     for (const ColumnAttribute& ca : attr)
@@ -1729,7 +1742,7 @@ void Grid::setColumnConfig(const std::vector<Grid::ColumnAttribute>& attr)
     }
 
     //"ownership" of visible columns is now within Grid
-    visibleCols = visCols;
+    visibleCols_ = visCols;
 
     updateWindowSizes();
     Refresh();
@@ -1739,10 +1752,10 @@ void Grid::setColumnConfig(const std::vector<Grid::ColumnAttribute>& attr)
 std::vector<Grid::ColumnAttribute> Grid::getColumnConfig() const
 {
     //get non-visible columns (+ outdated visible ones)
-    std::vector<ColumnAttribute> output = oldColAttributes;
+    std::vector<ColumnAttribute> output = oldColAttributes_;
 
-    auto iterVcols    = visibleCols.begin();
-    auto iterVcolsend = visibleCols.end();
+    auto iterVcols    = visibleCols_.begin();
+    auto iterVcolsend = visibleCols_.end();
 
     //update visible columns but keep order of non-visible ones!
     for (ColumnAttribute& ca : output)
@@ -1766,11 +1779,11 @@ std::vector<Grid::ColumnAttribute> Grid::getColumnConfig() const
 
 void Grid::showScrollBars(Grid::ScrollBarStatus horizontal, Grid::ScrollBarStatus vertical)
 {
-    if (showScrollbarX == horizontal &&
-        showScrollbarY == vertical) return; //support polling!
+    if (showScrollbarX_ == horizontal &&
+        showScrollbarY_ == vertical) return; //support polling!
 
-    showScrollbarX = horizontal;
-    showScrollbarY = vertical;
+    showScrollbarX_ = horizontal;
+    showScrollbarY_ = vertical;
 
 #if defined ZEN_WIN || defined ZEN_MAC
     //handled by Grid::SetScrollbar
@@ -1812,9 +1825,9 @@ void Grid::SetScrollbar(int orientation, int position, int thumbSize, int range,
 
     ScrollBarStatus sbStatus = SB_SHOW_AUTOMATIC;
     if (orientation == wxHORIZONTAL)
-        sbStatus = showScrollbarX;
+        sbStatus = showScrollbarX_;
     else if (orientation == wxVERTICAL)
-        sbStatus = showScrollbarY;
+        sbStatus = showScrollbarY_;
     else
         assert(false);
 
@@ -1851,7 +1864,7 @@ Opt<Grid::ColAction> Grid::clientPosToColumnAction(const wxPoint& pos) const
     const int absPosX = CalcUnscrolledPosition(pos).x;
     if (absPosX >= 0)
     {
-        const int resizeTolerance = allowColumnResize ? COLUMN_RESIZE_TOLERANCE : 0;
+        const int resizeTolerance = allowColumnResize_ ? COLUMN_RESIZE_TOLERANCE : 0;
         std::vector<ColumnWidth> absWidths = getColWidths(); //resolve stretched widths
 
         int accuWidth = 0;
@@ -1880,13 +1893,13 @@ Opt<Grid::ColAction> Grid::clientPosToColumnAction(const wxPoint& pos) const
 
 void Grid::moveColumn(size_t colFrom, size_t colTo)
 {
-    if (colFrom < visibleCols.size() &&
-        colTo   < visibleCols.size() &&
+    if (colFrom < visibleCols_.size() &&
+        colTo   < visibleCols_.size() &&
         colTo != colFrom)
     {
-        const VisibleColumn colAtt = visibleCols[colFrom];
-        visibleCols.erase (visibleCols.begin() + colFrom);
-        visibleCols.insert(visibleCols.begin() + colTo, colAtt);
+        const VisibleColumn colAtt = visibleCols_[colFrom];
+        visibleCols_.erase (visibleCols_.begin() + colFrom);
+        visibleCols_.insert(visibleCols_.begin() + colTo, colAtt);
     }
 }
 
@@ -1912,8 +1925,8 @@ ptrdiff_t Grid::clientPosToMoveTargetColumn(const wxPoint& pos) const
 
 ColumnType Grid::colToType(size_t col) const
 {
-    if (col < visibleCols.size())
-        return visibleCols[col].type_;
+    if (col < visibleCols_.size())
+        return visibleCols_[col].type_;
     return ColumnType::NONE;
 }
 
@@ -1976,7 +1989,7 @@ void Grid::setGridCursor(size_t row)
     mainWin_->setCursor(row, row);
     makeRowVisible(row);
 
-    selection.clear(); //clear selection, do NOT fire event
+    selection_.clear(); //clear selection, do NOT fire event
     selectRangeAndNotify(row, row, true /*positive*/, nullptr /*mouseInitiated*/); //set new selection + fire event
 
     mainWin_->Refresh();
@@ -1991,7 +2004,7 @@ void Grid::selectWithCursor(ptrdiff_t row)
     mainWin_->setCursor(row, anchorRow);
     makeRowVisible(row);
 
-    selection.clear(); //clear selection, do NOT fire event
+    selection_.clear(); //clear selection, do NOT fire event
     selectRangeAndNotify(anchorRow, row, true /*positive*/, nullptr /*mouseInitiated*/); //set new selection + fire event
 
     mainWin_->Refresh();
@@ -2050,7 +2063,7 @@ void Grid::selectRangeAndNotify(ptrdiff_t rowFrom, ptrdiff_t rowTo, bool positiv
     numeric::clamp<ptrdiff_t>(rowFirst, 0, rowCount);
     numeric::clamp<ptrdiff_t>(rowLast,  0, rowCount);
 
-    selection.selectRange(rowFirst, rowLast, positive);
+    selection_.selectRange(rowFirst, rowLast, positive);
 
     //notify event
     GridRangeSelectEvent selectionEvent(rowFirst, rowLast, positive, mouseInitiated);
@@ -2101,9 +2114,9 @@ size_t Grid::getGridCursor() const
 
 int Grid::getBestColumnSize(size_t col) const
 {
-    if (dataView_ && col < visibleCols.size())
+    if (dataView_ && col < visibleCols_.size())
     {
-        const ColumnType type = visibleCols[col].type_;
+        const ColumnType type = visibleCols_[col].type_;
 
         wxClientDC dc(mainWin_);
         dc.SetFont(mainWin_->GetFont()); //harmonize with MainWin::render()
@@ -2122,12 +2135,12 @@ int Grid::getBestColumnSize(size_t col) const
 
 void Grid::setColumnWidth(int width, size_t col, GridEventPolicy columnResizeEventPolicy, bool notifyAsync)
 {
-    if (col < visibleCols.size())
+    if (col < visibleCols_.size())
     {
-        VisibleColumn& vcRs = visibleCols[col];
+        VisibleColumn& vcRs = visibleCols_[col];
 
         const std::vector<int> stretchedWidths = getColStretchedWidths(mainWin_->GetClientSize().GetWidth());
-        if (stretchedWidths.size() != visibleCols.size())
+        if (stretchedWidths.size() != visibleCols_.size())
         {
             assert(false);
             return;
@@ -2146,9 +2159,9 @@ void Grid::setColumnWidth(int width, size_t col, GridEventPolicy columnResizeEve
         //2. shrink main window width so that horizontal scrollbars are shown despite the streched column
         //3. shrink a fixed-size column so that the scrollbars vanish and columns cover full width again
         //4. now verify that the stretched column is resizing immediately if main window is enlarged again
-        for (size_t col2 = 0; col2 < visibleCols.size(); ++col2)
-            if (visibleCols[col2].stretch_ > 0) //normalize stretched columns only
-                visibleCols[col2].offset_ = std::max(visibleCols[col2].offset_, COLUMN_MIN_WIDTH - stretchedWidths[col2]);
+        for (size_t col2 = 0; col2 < visibleCols_.size(); ++col2)
+            if (visibleCols_[col2].stretch_ > 0) //normalize stretched columns only
+                visibleCols_[col2].offset_ = std::max(visibleCols_[col2].offset_, COLUMN_MIN_WIDTH - stretchedWidths[col2]);
 
         if (columnResizeEventPolicy == ALLOW_GRID_EVENT)
         {
@@ -2169,9 +2182,9 @@ void Grid::setColumnWidth(int width, size_t col, GridEventPolicy columnResizeEve
 
 void Grid::autoSizeColumns(GridEventPolicy columnResizeEventPolicy)
 {
-    if (allowColumnResize)
+    if (allowColumnResize_)
     {
-        for (size_t col = 0; col < visibleCols.size(); ++col)
+        for (size_t col = 0; col < visibleCols_.size(); ++col)
         {
             const int bestWidth = getBestColumnSize(col); //return -1 on error
             if (bestWidth >= 0)
@@ -2188,7 +2201,7 @@ std::vector<int> Grid::getColStretchedWidths(int clientWidth) const //final widt
     assert(clientWidth >= 0);
     clientWidth = std::max(clientWidth, 0);
     int stretchTotal = 0;
-    for (const VisibleColumn& vc : visibleCols)
+    for (const VisibleColumn& vc : visibleCols_)
     {
         assert(vc.stretch_ >= 0);
         stretchTotal += vc.stretch_;
@@ -2199,28 +2212,27 @@ std::vector<int> Grid::getColStretchedWidths(int clientWidth) const //final widt
     std::vector<int> output;
 
     if (stretchTotal <= 0)
-        output.resize(visibleCols.size()); //fill with zeros
+        output.resize(visibleCols_.size()); //fill with zeros
     else
-        for (const VisibleColumn& vc : visibleCols)
+    {
+        for (const VisibleColumn& vc : visibleCols_)
         {
             const int width = clientWidth * vc.stretch_ / stretchTotal; //rounds down!
             output.push_back(width);
             remainingWidth -= width;
         }
 
-    //distribute *all* of clientWidth: should suffice to enlarge the first few stretched columns; no need to minimize total absolute error of distribution
-    if (stretchTotal > 0)
+        //distribute *all* of clientWidth: should suffice to enlarge the first few stretched columns; no need to minimize total absolute error of distribution
         if (remainingWidth > 0)
-        {
-            for (size_t col2 = 0; col2 < visibleCols.size(); ++col2)
-                if (visibleCols[col2].stretch_ > 0)
+            for (size_t col2 = 0; col2 < visibleCols_.size(); ++col2)
+                if (visibleCols_[col2].stretch_ > 0)
                 {
                     ++output[col2];
                     if (--remainingWidth == 0)
-                        return output;
+                        break;
                 }
-            assert(false);
-        }
+        assert(remainingWidth == 0);
+    }
     return output;
 }
 
@@ -2234,12 +2246,12 @@ std::vector<Grid::ColumnWidth> Grid::getColWidths() const
 std::vector<Grid::ColumnWidth> Grid::getColWidths(int mainWinWidth) const //evaluate stretched columns
 {
     const std::vector<int> stretchedWidths = getColStretchedWidths(mainWinWidth);
-    assert(stretchedWidths.size() == visibleCols.size());
+    assert(stretchedWidths.size() == visibleCols_.size());
 
     std::vector<ColumnWidth> output;
-    for (size_t col2 = 0; col2 < visibleCols.size(); ++col2)
+    for (size_t col2 = 0; col2 < visibleCols_.size(); ++col2)
     {
-        const auto& vc = visibleCols[col2];
+        const auto& vc = visibleCols_[col2];
         int width = stretchedWidths[col2] + vc.offset_;
 
         if (vc.stretch_ > 0)
diff --git a/wx+/grid.h b/wx+/grid.h
index b8b6711e..f08d6e41 100644
--- a/wx+/grid.h
+++ b/wx+/grid.h
@@ -178,7 +178,7 @@ public:
     //alternative until wxScrollHelper::ShowScrollbars() becomes available in wxWidgets 2.9
     void showScrollBars(ScrollBarStatus horizontal, ScrollBarStatus vertical);
 
-    std::vector<size_t> getSelectedRows() const { return selection.get(); }
+    std::vector<size_t> getSelectedRows() const { return selection_.get(); }
     void selectAllRows (GridEventPolicy rangeEventPolicy);
     void clearSelection(GridEventPolicy rangeEventPolicy); //turn off range selection event when calling this function in an event handler to avoid recursion!
 
@@ -202,8 +202,8 @@ public:
 
     void refreshCell(size_t row, ColumnType colType);
 
-    void enableColumnMove  (bool value) { allowColumnMove   = value; }
-    void enableColumnResize(bool value) { allowColumnResize = value; }
+    void enableColumnMove  (bool value) { allowColumnMove_   = value; }
+    void enableColumnResize(bool value) { allowColumnResize_ = value; }
 
     void setGridCursor(size_t row); //set + show + select cursor (+ emit range selection event)
     size_t getGridCursor() const; //returns row
@@ -301,7 +301,7 @@ private:
     };
     std::vector<ColumnWidth> getColWidths()                 const; //
     std::vector<ColumnWidth> getColWidths(int mainWinWidth) const; //evaluate stretched columns
-    int                                   getColWidthsSum(int mainWinWidth) const;
+    int                      getColWidthsSum(int mainWinWidth) const;
     std::vector<int> getColStretchedWidths(int clientWidth) const; //final width = (normalized) (stretchedWidth + offset)
 
     Opt<int> getColWidth(size_t col) const
@@ -318,7 +318,7 @@ private:
 
     void selectRangeAndNotify(ptrdiff_t rowFrom, ptrdiff_t rowTo, bool positive, const GridClickEvent* mouseInitiated); //select inclusive range [rowFrom, rowTo] + notify event!
 
-    bool isSelected(size_t row) const { return selection.isSelected(row); }
+    bool isSelected(size_t row) const { return selection_.isSelected(row); }
 
     struct ColAction
     {
@@ -345,21 +345,21 @@ private:
     ColLabelWin* colLabelWin_;
     MainWin*     mainWin_;
 
-    ScrollBarStatus showScrollbarX = SB_SHOW_AUTOMATIC;
-    ScrollBarStatus showScrollbarY = SB_SHOW_AUTOMATIC;
+    ScrollBarStatus showScrollbarX_ = SB_SHOW_AUTOMATIC;
+    ScrollBarStatus showScrollbarY_ = SB_SHOW_AUTOMATIC;
 
     int colLabelHeight_ = 0;
-    bool drawRowLabel = true;
+    bool drawRowLabel_ = true;
 
     std::shared_ptr<GridData> dataView_;
-    Selection selection;
-    bool allowColumnMove   = true;
-    bool allowColumnResize = true;
+    Selection selection_;
+    bool allowColumnMove_   = true;
+    bool allowColumnResize_ = true;
 
-    std::vector<VisibleColumn> visibleCols; //individual widths, type and total column count
-    std::vector<ColumnAttribute> oldColAttributes; //visible + nonvisible columns; use for conversion in setColumnConfig()/getColumnConfig() *only*!
+    std::vector<VisibleColumn>   visibleCols_; //individual widths, type and total column count
+    std::vector<ColumnAttribute> oldColAttributes_; //visible + nonvisible columns; use for conversion in setColumnConfig()/getColumnConfig() *only*!
 
-    size_t rowCountOld = 0; //at the time of last Grid::Refresh()
+    size_t rowCountOld_ = 0; //at the time of last Grid::Refresh()
 };
 }
 
diff --git a/wx+/http.cpp b/wx+/http.cpp
index ce3de482..3428546e 100644
--- a/wx+/http.cpp
+++ b/wx+/http.cpp
@@ -31,186 +31,259 @@ namespace
     #endif
 #endif
 
+struct UrlRedirectError
+{
+    UrlRedirectError(const std::wstring& url) : newUrl(url) {}
+    std::wstring newUrl;
+};
+}
 
-std::string sendHttpRequestImpl(const std::wstring& url, //throw SysError
-                                const std::wstring& userAgent,
-                                const std::string* postParams, //issue POST if bound, GET otherwise
-                                int level = 0)
+
+class HttpInputStream::Impl
 {
-    assert(!startsWith(makeUpperCopy(url), L"HTTPS:")); //not supported by wxHTTP!
-    const std::wstring urlFmt = startsWith(makeUpperCopy(url), L"HTTP://") ? afterFirst(url, L"://", IF_MISSING_RETURN_NONE) : url;
-    const std::wstring server =       beforeFirst(urlFmt, L'/', IF_MISSING_RETURN_ALL);
-    const std::wstring page   = L'/' + afterFirst(urlFmt, L'/', IF_MISSING_RETURN_NONE);
+public:
+    Impl(const std::wstring& url, const std::wstring& userAgent, //throw SysError, UrlRedirectError
+         const std::string* postParams) //issue POST if bound, GET otherwise
+    {
+        ZEN_ON_SCOPE_FAIL( cleanup(); /*destructor call would lead to member double clean-up!!!*/ );
+
+        assert(!startsWith(makeUpperCopy(url), L"HTTPS:")); //not supported by wxHTTP!
+        const std::wstring urlFmt = startsWith(makeUpperCopy(url), L"HTTP://") ||
+                                    startsWith(makeUpperCopy(url), L"HTTPS://") ? afterFirst(url, L"://", IF_MISSING_RETURN_NONE) : url;
+        const std::wstring server =       beforeFirst(urlFmt, L'/', IF_MISSING_RETURN_ALL);
+        const std::wstring page   = L'/' + afterFirst(urlFmt, L'/', IF_MISSING_RETURN_NONE);
 
 #ifdef ZEN_WIN
-    //WinInet: 1. uses IE proxy settings! :) 2. follows HTTP redirects by default 3. swallows HTTPS if needed
-    HINTERNET hInternet = ::InternetOpen(userAgent.c_str(),            //_In_  LPCTSTR lpszAgent,
-                                         INTERNET_OPEN_TYPE_PRECONFIG, //_In_  DWORD dwAccessType,
-                                         nullptr, //_In_  LPCTSTR lpszProxyName,
-                                         nullptr, //_In_  LPCTSTR lpszProxyBypass,
-                                         0);      //_In_  DWORD dwFlags
-    if (!hInternet)
-        THROW_LAST_SYS_ERROR(L"InternetOpen");
-    ZEN_ON_SCOPE_EXIT(::InternetCloseHandle(hInternet));
+        //WinInet: 1. uses IE proxy settings! :) 2. follows HTTP redirects by default 3. swallows HTTPS if needed
+        hInternet_ = ::InternetOpen(userAgent.c_str(),            //_In_  LPCTSTR lpszAgent,
+                                    INTERNET_OPEN_TYPE_PRECONFIG, //_In_  DWORD dwAccessType,
+                                    nullptr, //_In_  LPCTSTR lpszProxyName,
+                                    nullptr, //_In_  LPCTSTR lpszProxyBypass,
+                                    0);      //_In_  DWORD dwFlags
+        if (!hInternet_)
+            THROW_LAST_SYS_ERROR(L"InternetOpen");
+
+        hSession_ = ::InternetConnect(hInternet_,     //_In_ HINTERNET     hInternet,
+                                      server.c_str(), //_In_ LPCTSTR       lpszServerName,
+                                      INTERNET_DEFAULT_HTTP_PORT, //_In_ INTERNET_PORT nServerPort,
+                                      nullptr,        //_In_ LPCTSTR       lpszUsername,
+                                      nullptr,        //_In_ LPCTSTR       lpszPassword,
+                                      INTERNET_SERVICE_HTTP, //_In_ DWORD         dwService,
+                                      0,              //_In_ DWORD         dwFlags,
+                                      0);             //_In_ DWORD_PTR     dwContext
+        if (!hSession_)
+            THROW_LAST_SYS_ERROR(L"InternetConnect");
+
+        const wchar_t* acceptTypes[] = { L"*/*", nullptr };
+        DWORD requestFlags =
+            //INTERNET_FLAG_KEEP_CONNECTION |
+            //      the combination 1. INTERNET_FLAG_KEEP_CONNECTION (= adds "Connection: Keep-Alive" but NOT "Keep-Alive: timeout" to the header)
+            //                      2. *no* "Keep-Alive: timeout" header entry 3. call from within VM and 4. *no* Fiddler running 5. HTTP POST
+            //      leads to Godaddy blocking the IP: http://www.freefilesync.org/forum/viewtopic.php?t=3855
+            //      => it seems a broken keep alive header is the trigger: But why is it then working outside the VM or when Fiddler is running??? Why not a problem for HTTP GET?
+            //          note: HTTP/1.1 has keep-alive semantics by default, so this flag is probably useless anyway
+            INTERNET_FLAG_NO_UI;
+
+        if (postParams)
+        {
+            requestFlags |= INTERNET_FLAG_NO_AUTO_REDIRECT; //POST would be re-issued as GET during auto-redirect => handle ourselves!
+        }
+        else //HTTP GET
+        {
+            requestFlags |= INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTPS | INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTP;
+            requestFlags |= INTERNET_FLAG_RELOAD; //not relevant for POST (= never cached)
+        }
 
-    HINTERNET hSession = ::InternetConnect(hInternet,      //_In_ HINTERNET     hInternet,
-                                           server.c_str(), //_In_ LPCTSTR       lpszServerName,
-                                           INTERNET_DEFAULT_HTTP_PORT, //_In_ INTERNET_PORT nServerPort,
-                                           nullptr,        //_In_ LPCTSTR       lpszUsername,
-                                           nullptr,        //_In_ LPCTSTR       lpszPassword,
-                                           INTERNET_SERVICE_HTTP, //_In_ DWORD         dwService,
-                                           0,              //_In_ DWORD         dwFlags,
-                                           0);             //_In_ DWORD_PTR     dwContext
-    if (!hSession)
-        THROW_LAST_SYS_ERROR(L"InternetConnect");
-    ZEN_ON_SCOPE_EXIT(::InternetCloseHandle(hSession));
-
-    const wchar_t* acceptTypes[] = { L"*/*", nullptr };
-    DWORD requestFlags = 
-		//INTERNET_FLAG_KEEP_CONNECTION |
-		//		the combination 1. INTERNET_FLAG_KEEP_CONNECTION (= adds "Connection: Keep-Alive" but NOT "Keep-Alive: timeout" to the header)
-		//						2. *no* "Keep-Alive: timeout" header entry 3. call from within VM and 4. *no* Fiddler running 5. HTTP POST
-		//		leads to Godaddy blocking the IP: http://www.freefilesync.org/forum/viewtopic.php?t=3855
-		//		=> it seems a broken keep alive header is the trigger: But why is it then working outside the VM or when Fiddler is running??? Why not a problem for HTTP GET?
-		//			note: HTTP/1.1 has keep-alive semantics by default, so this flag is probably useless anyway
-                         INTERNET_FLAG_NO_UI;
-
-    if (postParams)
-	{
-		requestFlags |= INTERNET_FLAG_NO_AUTO_REDIRECT; //POST would be re-issued as GET during auto-redirect => handle ourselves!
-	}
-	else //HTTP GET
-	{
-		requestFlags |= INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTPS | INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTP;
-		requestFlags |= INTERNET_FLAG_RELOAD; //not relevant for POST (= never cached)
-	}
-
-    HINTERNET hRequest = ::HttpOpenRequest(hSession,     //_In_ HINTERNET hConnect,
-                                           postParams ? L"POST" : L"GET", //_In_ LPCTSTR   lpszVerb,
-                                           page.c_str(), //_In_ LPCTSTR   lpszObjectName,
-                                           nullptr,      //_In_ LPCTSTR   lpszVersion,
-                                           nullptr,      //_In_ LPCTSTR   lpszReferer,
-                                           acceptTypes,  //_In_ LPCTSTR   *lplpszAcceptTypes,
-                                           requestFlags, //_In_ DWORD     dwFlags,
-                                           0); //_In_ DWORD_PTR dwContext
-    if (!hRequest)
-        THROW_LAST_SYS_ERROR(L"HttpOpenRequest");
-    ZEN_ON_SCOPE_EXIT(::InternetCloseHandle(hRequest));
+        hRequest_ = ::HttpOpenRequest(hSession_,    //_In_ HINTERNET hConnect,
+                                      postParams ? L"POST" : L"GET", //_In_ LPCTSTR   lpszVerb,
+                                      page.c_str(), //_In_ LPCTSTR   lpszObjectName,
+                                      nullptr,      //_In_ LPCTSTR   lpszVersion,
+                                      nullptr,      //_In_ LPCTSTR   lpszReferer,
+                                      acceptTypes,  //_In_ LPCTSTR   *lplpszAcceptTypes,
+                                      requestFlags, //_In_ DWORD     dwFlags,
+                                      0); //_In_ DWORD_PTR dwContext
+        if (!hRequest_)
+            THROW_LAST_SYS_ERROR(L"HttpOpenRequest");
 
-     const std::wstring headers = postParams ? L"Content-type: application/x-www-form-urlencoded" : L"";
+        const std::wstring headers = postParams ? L"Content-type: application/x-www-form-urlencoded" : L"";
 
-	assert(std::all_of(headers.begin(), headers.end(), [](wchar_t c){ return makeUnsigned(c) < 128; }));
-	//HttpSendRequest has finicky behavior for non-ASCII headers: https://msdn.microsoft.com/en-us/library/windows/desktop/aa384247
+        assert(std::all_of(headers.begin(), headers.end(), [](wchar_t c) { return makeUnsigned(c) < 128; }));
+        //HttpSendRequest has finicky behavior for non-ASCII headers: https://msdn.microsoft.com/en-us/library/windows/desktop/aa384247
 
-    std::string postParamsBuf = postParams ? *postParams : "";
+        std::string postParamsBuf = postParams ? *postParams : "";
 
-    if (!::HttpSendRequest(hRequest,              //_In_ HINTERNET hRequest,
-                           headers.c_str(),       //_In_ LPCTSTR   lpszHeaders,
-                           static_cast<DWORD>(headers.size()),                  //_In_ DWORD     dwHeadersLength,
-                           postParamsBuf.empty() ? nullptr : &postParamsBuf[0], //_In_ LPVOID    lpOptional,
-                           static_cast<DWORD>(postParamsBuf.size())))           //_In_ DWORD     dwOptionalLength
-        THROW_LAST_SYS_ERROR(L"HttpSendRequest");
+        if (!::HttpSendRequest(hRequest_,             //_In_ HINTERNET hRequest,
+                               headers.c_str(),       //_In_ LPCTSTR   lpszHeaders,
+                               static_cast<DWORD>(headers.size()),                  //_In_ DWORD     dwHeadersLength,
+                               postParamsBuf.empty() ? nullptr : &postParamsBuf[0], //_In_ LPVOID    lpOptional,
+                               static_cast<DWORD>(postParamsBuf.size())))           //_In_ DWORD     dwOptionalLength
+            THROW_LAST_SYS_ERROR(L"HttpSendRequest");
 
-    DWORD sc = 0;
-    {
-        DWORD bufLen = sizeof(sc);
-        if (!::HttpQueryInfo(hRequest, //_In_     HINTERNET hRequest,
-                             HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER, //_In_     DWORD dwInfoLevel,
-                             &sc,      //_Inout_  LPVOID lpvBuffer,
-                             &bufLen,  //_Inout_  LPDWORD lpdwBufferLength,
-                             nullptr)) //_Inout_  LPDWORD lpdwIndex
-            THROW_LAST_SYS_ERROR(L"HttpQueryInfo: HTTP_QUERY_STATUS_CODE");
-    }
+        DWORD sc = 0;
+        {
+            DWORD bufLen = sizeof(sc);
+            if (!::HttpQueryInfo(hRequest_, //_In_     HINTERNET hRequest,
+                                 HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER, //_In_     DWORD dwInfoLevel,
+                                 &sc,       //_Inout_  LPVOID lpvBuffer,
+                                 &bufLen,   //_Inout_  LPDWORD lpdwBufferLength,
+                                 nullptr))  //_Inout_  LPDWORD lpdwIndex
+                THROW_LAST_SYS_ERROR(L"HttpQueryInfo: HTTP_QUERY_STATUS_CODE");
+        }
 
-    //http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#3xx_Redirection
-    if (sc / 100 == 3) //e.g. 301, 302, 303, 307... we're not too greedy since we check location, too!
-    {
-        if (level < 5) //"A user agent should not automatically redirect a request more than five times, since such redirections usually indicate an infinite loop."
+        //http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#3xx_Redirection
+        if (sc / 100 == 3) //e.g. 301, 302, 303, 307... we're not too greedy since we check location, too!
         {
             DWORD bufLen = 10000;
             std::wstring location(bufLen, L'\0');
-            if (!::HttpQueryInfo(hRequest, HTTP_QUERY_LOCATION, &*location.begin(), &bufLen, nullptr))
+            if (!::HttpQueryInfo(hRequest_, HTTP_QUERY_LOCATION, &*location.begin(), &bufLen, nullptr))
                 THROW_LAST_SYS_ERROR(L"HttpQueryInfo: HTTP_QUERY_LOCATION");
             if (bufLen >= location.size()) //HttpQueryInfo expected to write terminating zero
                 throw SysError(L"HttpQueryInfo: HTTP_QUERY_LOCATION, buffer overflow");
             location.resize(bufLen);
 
-            if (!location.empty())
-                return sendHttpRequestImpl(location, userAgent, postParams, level + 1);
+            if (location.empty())
+                throw SysError(L"Unresolvable redirect. Empty target Location.");
+
+            throw UrlRedirectError(location);
+        }
+
+        if (sc != HTTP_STATUS_OK) //200
+            throw SysError(replaceCpy<std::wstring>(L"HTTP status code %x.", L"%x", numberTo<std::wstring>(sc)));
+        //e.g. 404 - HTTP_STATUS_NOT_FOUND
+
+#else
+        assert(std::this_thread::get_id() == mainThreadId);
+        assert(wxApp::IsMainLoopRunning());
+
+        webAccess_.SetHeader(L"User-Agent", userAgent);
+        webAccess_.SetTimeout(10 /*[s]*/); //default: 10 minutes: WTF are these wxWidgets people thinking???
+
+        if (!webAccess_.Connect(server)) //will *not* fail for non-reachable url here!
+            throw SysError(L"wxHTTP::Connect");
+
+        if (postParams)
+            if (!webAccess_.SetPostText(L"application/x-www-form-urlencoded", utfCvrtTo<wxString>(*postParams)))
+                throw SysError(L"wxHTTP::SetPostText");
+
+        httpStream_.reset(webAccess_.GetInputStream(page)); //pass ownership
+        const int sc = webAccess_.GetResponse();
+
+        //http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#3xx_Redirection
+        if (sc / 100 == 3) //e.g. 301, 302, 303, 307... we're not too greedy since we check location, too!
+        {
+            const std::wstring newUrl(webAccess_.GetHeader(L"Location"));
+            if (newUrl.empty())
+                throw SysError(L"Unresolvable redirect. Empty target Location.");
+
+            throw UrlRedirectError(newUrl);
         }
-        throw SysError(L"Unresolvable redirect.");
+
+        if (sc != 200) //HTTP_STATUS_OK
+            throw SysError(replaceCpy<std::wstring>(L"HTTP status code %x.", L"%x", numberTo<std::wstring>(sc)));
+
+        if (!httpStream_ || webAccess_.GetError() != wxPROTO_NOERR)
+            throw SysError(L"wxHTTP::GetError (" + numberTo<std::wstring>(webAccess_.GetError()) + L")");
+#endif
     }
 
-    if (sc != HTTP_STATUS_OK) //200
-        throw SysError(replaceCpy<std::wstring>(L"HTTP status code %x.", L"%x", numberTo<std::wstring>(sc)));
-    //e.g. 404 - HTTP_STATUS_NOT_FOUND
+    ~Impl() { cleanup(); }
 
-    std::string buffer;
-    const DWORD blockSize = 64 * 1024;
-    //internet says "HttpQueryInfo() + HTTP_QUERY_CONTENT_LENGTH" not supported by all http servers...
-    for (;;)
+    size_t tryRead(void* buffer, size_t bytesToRead) //throw SysError; may return short, only 0 means EOF!
     {
-        buffer.resize(buffer.size() + blockSize);
+        if (bytesToRead == 0) //"read() with a count of 0 returns zero" => indistinguishable from end of file! => check!
+            throw std::logic_error("Contract violation! " + std::string(__FILE__) + ":" + numberTo<std::string>(__LINE__));
 
+#ifdef ZEN_WIN
+        //"HttpQueryInfo() + HTTP_QUERY_CONTENT_LENGTH" not supported by all http servers...
         DWORD bytesRead = 0;
-        if (!::InternetReadFile(hRequest,    //_In_   HINTERNET hFile,
-                                &*(buffer.begin() + buffer.size() - blockSize),  //_Out_  LPVOID lpBuffer,
-                                blockSize,   //_In_   DWORD dwNumberOfBytesToRead,
+        if (!::InternetReadFile(hRequest_,   //_In_   HINTERNET hFile,
+                                buffer,      //_Out_  LPVOID lpBuffer,
+                                static_cast<DWORD>(bytesToRead), //_In_   DWORD dwNumberOfBytesToRead,
                                 &bytesRead)) //_Out_  LPDWORD lpdwNumberOfBytesRead
             THROW_LAST_SYS_ERROR(L"InternetReadFile");
+#else
+        httpStream_->Read(buffer, bytesToRead);
 
-        if (bytesRead > blockSize) //better safe than sorry
+        const wxStreamError ec = httpStream_->GetLastError();
+        if (ec != wxSTREAM_NO_ERROR && ec != wxSTREAM_EOF)
+            throw SysError(L"wxInputStream::GetLastError (" + numberTo<std::wstring>(httpStream_->GetLastError()) + L")");
+
+        const size_t bytesRead = httpStream_->LastRead();
+        //"if there are not enough bytes in the stream right now, LastRead() value will be
+        // less than size but greater than 0. If it is 0, it means that EOF has been reached."
+        assert(bytesRead > 0 || ec == wxSTREAM_EOF);
+#endif
+        if (bytesRead > bytesToRead) //better safe than sorry
             throw SysError(L"InternetReadFile: buffer overflow.");
 
-        if (bytesRead < blockSize)
-            buffer.resize(buffer.size() - (blockSize - bytesRead)); //caveat: unsigned arithmetics
+        return bytesRead; //"zero indicates end of file"
+    }
 
-        if (bytesRead == 0)
-            return buffer;
+private:
+    Impl           (const Impl&) = delete;
+    Impl& operator=(const Impl&) = delete;
+
+    void cleanup()
+    {
+#ifdef ZEN_WIN
+        if (hRequest_ ) ::InternetCloseHandle(hRequest_);
+        if (hSession_ ) ::InternetCloseHandle(hSession_);
+        if (hInternet_) ::InternetCloseHandle(hInternet_);
+#endif
     }
 
+#ifdef ZEN_WIN
+    HINTERNET hInternet_ = nullptr;
+    HINTERNET hSession_  = nullptr;
+    HINTERNET hRequest_  = nullptr;
 #else
-    assert(std::this_thread::get_id() == mainThreadId);
-    assert(wxApp::IsMainLoopRunning());
+    wxHTTP webAccess_;
+    std::unique_ptr<wxInputStream> httpStream_; //must be deleted BEFORE webAccess is closed
+#endif
+};
 
-    wxHTTP webAccess;
-    webAccess.SetHeader(L"User-Agent", userAgent);
-    webAccess.SetTimeout(10 /*[s]*/); //default: 10 minutes: WTF are these wxWidgets people thinking???
 
-    if (!webAccess.Connect(server)) //will *not* fail for non-reachable url here!
-        throw SysError(L"wxHTTP::Connect");
+HttpInputStream::HttpInputStream(std::unique_ptr<Impl>&& pimpl) : pimpl_(std::move(pimpl)) {}
 
-    if (postParams)
-        if (!webAccess.SetPostText(L"application/x-www-form-urlencoded", utfCvrtTo<wxString>(*postParams)))
-            throw SysError(L"wxHTTP::SetPostText");
+HttpInputStream::~HttpInputStream() {}
 
-    std::unique_ptr<wxInputStream> httpStream(webAccess.GetInputStream(page)); //must be deleted BEFORE webAccess is closed
-    const int sc = webAccess.GetResponse();
+size_t HttpInputStream::tryRead(void* buffer, size_t bytesToRead) { return pimpl_->tryRead(buffer, bytesToRead); } //throw SysError
+
+
+std::string HttpInputStream::readAll() //throw SysError
+{
+    std::string buffer;
+    const size_t blockSize = getBlockSize();
 
-    //http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#3xx_Redirection
-    if (sc / 100 == 3) //e.g. 301, 302, 303, 307... we're not too greedy since we check location, too!
+    for (;;)
     {
-        if (level < 5) //"A user agent should not automatically redirect a request more than five times, since such redirections usually indicate an infinite loop."
-        {
-            const std::wstring newUrl(webAccess.GetHeader(L"Location"));
-            if (!newUrl.empty())
-                return sendHttpRequestImpl(newUrl, userAgent, postParams, level + 1);
-        }
-        throw SysError(L"Unresolvable redirect.");
-    }
+        buffer.resize(buffer.size() + blockSize);
 
-    if (sc != 200) //HTTP_STATUS_OK
-        throw SysError(replaceCpy<std::wstring>(L"HTTP status code %x.", L"%x", numberTo<std::wstring>(sc)));
+        const size_t bytesRead = pimpl_->tryRead(&*(buffer.end() - blockSize), blockSize); //throw SysError
 
-    if (!httpStream || webAccess.GetError() != wxPROTO_NOERR)
-        throw SysError(L"wxHTTP::GetError");
+        if (bytesRead < blockSize)
+            buffer.resize(buffer.size() - (blockSize - bytesRead)); //caveat: unsigned arithmetics
 
-    std::string buffer;
-    int newValue = 0;
-    while ((newValue = httpStream->GetC()) != wxEOF)
-        buffer.push_back(static_cast<char>(newValue));
-    return buffer;
-#endif
+        if (bytesRead == 0)
+            return buffer;
+    }
+}
+
+
+namespace
+{
+std::unique_ptr<HttpInputStream::Impl> sendHttpRequestImpl(const std::wstring& url, const std::wstring& userAgent, //throw SysError
+                                                           const std::string* postParams) //issue POST if bound, GET otherwise
+{
+    std::wstring urlRed =  url;
+    //"A user agent should not automatically redirect a request more than five times, since such redirections usually indicate an infinite loop."
+    for (int redirects = 0; redirects < 6; ++redirects)
+        try
+        {
+            return std::make_unique<HttpInputStream::Impl>(urlRed, userAgent, postParams); //throw SysError, UrlRedirectError
+        }
+        catch (const UrlRedirectError& e) { urlRed = e.newUrl; }
+    throw SysError(L"Too many redirects.");
 }
 
 
@@ -228,31 +301,72 @@ std::string urlencode(const std::string& str)
             out += c;
         else
         {
-            const char hexDigits[] = "0123456789ABCDEF";
+            const std::pair<char, char> hex = hexify(c);
+
             out += '%';
-            out += hexDigits[static_cast<unsigned char>(c) / 16];
-            out += hexDigits[static_cast<unsigned char>(c) % 16];
+            out += hex.first;
+            out += hex.second;
+        }
+    return out;
+}
+
+
+std::string urldecode(const std::string& str)
+{
+    std::string out;
+    for (size_t i = 0; i < str.size(); ++i)
+    {
+        const char c = str[i];
+        if (c == '+')
+            out += ' ';
+        else if (c == '%' && str.size() - i >= 3 &&
+                 isHexDigit(str[i + 1]) &&
+                 isHexDigit(str[i + 2]))
+        {
+            out += unhexify(str[i + 1], str[i + 2]);
+            i += 2;
         }
+        else
+            out += c;
+    }
     return out;
 }
 }
 
 
-std::string zen::sendHttpPost(const std::wstring& url, const std::wstring& userAgent, const std::vector<std::pair<std::string, std::string>>& postParams) //throw SysError
+std::string zen::xWwwFormUrlEncode(const std::vector<std::pair<std::string, std::string>>& paramPairs)
 {
-    //convert post parameters into "application/x-www-form-urlencoded"
-    std::string flatParams;
-    for (const auto& pair : postParams)
-        flatParams += urlencode(pair.first) + '=' + urlencode(pair.second) + '&';
+    std::string output;
+    for (const auto& pair : paramPairs)
+        output += urlencode(pair.first) + '=' + urlencode(pair.second) + '&';
     //encode both key and value: https://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1
-    if (!flatParams.empty())
-        flatParams.pop_back();
+    if (!output.empty())
+        output.pop_back();
+    return output;
+}
 
-    return sendHttpRequestImpl(url, userAgent, &flatParams); //throw SysError
+
+std::vector<std::pair<std::string, std::string>> zen::xWwwFormUrlDecode(const std::string& str)
+{
+    std::vector<std::pair<std::string, std::string>> output;
+
+    for (const std::string& nvPair : split(str, '&'))
+        if (!nvPair.empty())
+            output.emplace_back(urldecode(beforeFirst(nvPair, '=', IF_MISSING_RETURN_ALL)),
+                                urldecode(afterFirst (nvPair, '=', IF_MISSING_RETURN_NONE)));
+    return output;
+}
+
+
+HttpInputStream zen::sendHttpPost(const std::wstring& url, const std::wstring& userAgent,
+                                  const std::vector<std::pair<std::string, std::string>>& postParams) //throw SysError
+{
+    const std::string encodedParams = xWwwFormUrlEncode(postParams);
+    return sendHttpRequestImpl(url, userAgent, &encodedParams); //throw SysError
 }
 
 
-std::string zen::sendHttpGet(const std::wstring& url, const std::wstring& userAgent) //throw SysError
+HttpInputStream zen::sendHttpGet(const std::wstring& url, const std::wstring& userAgent) //throw SysError
 {
     return sendHttpRequestImpl(url, userAgent, nullptr); //throw SysError
 }
diff --git a/wx+/http.h b/wx+/http.h
index febe8f24..cf385d5e 100644
--- a/wx+/http.h
+++ b/wx+/http.h
@@ -17,9 +17,32 @@ namespace zen
     Windows: WinInet-based   => may be called from worker thread
     Linux:   wxWidgets-based => don't call from worker thread
 */
-std::string sendHttpPost(const std::wstring& url, const std::wstring& userAgent, const std::vector<std::pair<std::string, std::string>>& postParams); //throw SysError
-std::string sendHttpGet (const std::wstring& url, const std::wstring& userAgent); //throw SysError
+class HttpInputStream
+{
+public:
+    std::string readAll(); //throw SysError
+
+    //support zen/serialize.h Unbuffered Input Stream Concept
+    size_t tryRead(void* buffer, size_t bytesToRead); //throw SysError; may return short, only 0 means EOF! =>  CONTRACT: bytesToRead > 0!
+    size_t getBlockSize() const { return 64 * 1024; }
+
+    class Impl;
+    HttpInputStream(std::unique_ptr<Impl>&& pimpl);
+    HttpInputStream(HttpInputStream&&) = default;
+    ~HttpInputStream();
+
+private:
+    std::unique_ptr<Impl> pimpl_;
+};
+
+
+HttpInputStream sendHttpGet (const std::wstring& url, const std::wstring& userAgent); //throw SysError
+HttpInputStream sendHttpPost(const std::wstring& url, const std::wstring& userAgent,
+                             const std::vector<std::pair<std::string, std::string>>& postParams); //throw SysError
 bool internetIsAlive(); //noexcept
+
+std::string xWwwFormUrlEncode(const std::vector<std::pair<std::string, std::string>>& paramPairs);
+std::vector<std::pair<std::string, std::string>> xWwwFormUrlDecode(const std::string& str);
 }
 
 #endif //HTTP_h_879083425703425702
diff --git a/wx+/image_tools.cpp b/wx+/image_tools.cpp
index a6ecc3d3..90945a44 100644
--- a/wx+/image_tools.cpp
+++ b/wx+/image_tools.cpp
@@ -160,7 +160,7 @@ wxImage zen::createImageFromText(const wxString& text, const wxFont& font, const
 
         //for some reason wxDC::DrawText messes up "weak" bidi characters even when wxLayout_RightToLeft is set! (--> arrows in hebrew/arabic)
         //=> use mark characters instead:
-        const wchar_t rtlMark = L'\u200F';
+        const wchar_t rtlMark = L'\u200F'; //UTF-8: E2 80 8F
         if (wxTheApp->GetLayoutDirection() == wxLayout_RightToLeft)
             textFmt = rtlMark + textFmt + rtlMark;
 
diff --git a/wx+/popup_dlg.cpp b/wx+/popup_dlg.cpp
index 918f44a5..f96884d9 100644
--- a/wx+/popup_dlg.cpp
+++ b/wx+/popup_dlg.cpp
@@ -86,27 +86,31 @@ public:
 #ifdef ZEN_WIN
         new zen::MouseMoveWindow(*this); //allow moving main dialog by clicking (nearly) anywhere...; ownership passed to "this"
 #endif
-        wxString titleTmp = cfg.title;
+        wxBitmap iconTmp;
+        wxString titleTmp;
         switch (type)
         {
             case DialogInfoType::INFO:
-                //"information" is meaningless as caption text!
+                //"Information" is meaningless as caption text!
                 //confirmation doesn't use info icon
-                //m_bitmapMsgType->Hide();
-                //m_bitmapMsgType->SetSize(30, -1);
-                //m_bitmapMsgType->SetBitmap(getResourceImage(L"msg_info"));
+                //iconTmp  = getResourceImage(L"msg_info");
                 break;
             case DialogInfoType::WARNING:
-                if (titleTmp.empty()) titleTmp = _("Warning");
-                m_bitmapMsgType->SetBitmap(getResourceImage(L"msg_warning"));
+                iconTmp  = getResourceImage(L"msg_warning");
+                titleTmp = _("Warning");
                 break;
             case DialogInfoType::ERROR2:
-                if (titleTmp.empty()) titleTmp = _("Error");
-                m_bitmapMsgType->SetBitmap(getResourceImage(L"msg_error"));
+                iconTmp  = getResourceImage(L"msg_error");
+                titleTmp = _("Error");
                 break;
         }
         if (cfg.icon.IsOk())
-            m_bitmapMsgType->SetBitmap(cfg.icon);
+            iconTmp = cfg.icon;
+
+        if (!cfg.title.empty())
+            titleTmp = cfg.title;
+        //-----------------------------------------------
+        m_bitmapMsgType->SetBitmap(iconTmp);
 
         if (titleTmp.empty())
             SetTitle(wxTheApp->GetAppDisplayName());
@@ -140,7 +144,7 @@ public:
 
         if (!cfg.textDetail.empty())
         {
-            const wxString& text = L"\n" + cfg.textDetail + L"\n"; //add empty top/bottom lines *instead* of using border space!
+            const wxString& text = L"\n" + trimCpy(cfg.textDetail) + L"\n"; //add empty top/bottom lines *instead* of using border space!
             setBestInitialSize(*m_textCtrlTextDetail, text, wxSize(maxWidth, maxHeight));
             m_textCtrlTextDetail->ChangeValue(text);
         }
@@ -185,14 +189,14 @@ private:
     void OnButtonAffirmative(wxCommandEvent& event) override
     {
         if (checkBoxValue_)
-            * checkBoxValue_ = m_checkBoxCustom->GetValue();
+            *checkBoxValue_ = m_checkBoxCustom->GetValue();
         EndModal(static_cast<int>(ConfirmationButton3::DO_IT));
     }
 
     void OnButtonNegative(wxCommandEvent& event) override
     {
         if (checkBoxValue_)
-            * checkBoxValue_ = m_checkBoxCustom->GetValue();
+            *checkBoxValue_ = m_checkBoxCustom->GetValue();
         EndModal(static_cast<int>(ConfirmationButton3::DONT_DO_IT));
     }
 
@@ -244,8 +248,8 @@ class zen::ConfirmationDialog3 : public StandardPopupDialog
 {
 public:
     ConfirmationDialog3(wxWindow* parent, DialogInfoType type, const PopupDialogCfg3& cfg, const wxString& labelDoIt, const wxString& labelDontDoIt) :
-        StandardPopupDialog(parent, type, cfg.pdCfg),
-        buttonToDisableWhenChecked(cfg.buttonToDisableWhenChecked)
+        StandardPopupDialog(parent, type, cfg.pdCfg_),
+        buttonToDisableWhenChecked_(cfg.buttonToDisableWhenChecked_)
     {
         assert(contains(labelDoIt,     L"&"));
         assert(contains(labelDontDoIt, L"&"));
@@ -269,7 +273,7 @@ private:
 
     void updateGui()
     {
-        switch (buttonToDisableWhenChecked)
+        switch (buttonToDisableWhenChecked_)
         {
             case ConfirmationButton3::DO_IT:
                 m_buttonAffirmative->Enable(!m_checkBoxCustom->GetValue());
@@ -282,7 +286,7 @@ private:
         }
     }
 
-    const ConfirmationButton3 buttonToDisableWhenChecked;
+    const ConfirmationButton3 buttonToDisableWhenChecked_;
 };
 
 //########################################################################################
diff --git a/wx+/popup_dlg.h b/wx+/popup_dlg.h
index 892c7a83..67f73a11 100644
--- a/wx+/popup_dlg.h
+++ b/wx+/popup_dlg.h
@@ -39,7 +39,7 @@ enum class ConfirmationButton3
 
 enum class ConfirmationButton
 {
-    DO_IT  = static_cast<int>(ConfirmationButton3::DO_IT), //[!]
+    DO_IT  = static_cast<int>(ConfirmationButton3::DO_IT ), //[!]
     CANCEL = static_cast<int>(ConfirmationButton3::CANCEL), //Clang requires a "static_cast"
 };
 
@@ -73,23 +73,24 @@ private:
 
 struct PopupDialogCfg3
 {
-    PopupDialogCfg3& setTitle             (const wxString& label) { pdCfg.setTitle             (label); return *this; }
-    PopupDialogCfg3& setMainInstructions  (const wxString& label) { pdCfg.setMainInstructions  (label); return *this; } //set at least one of these!
-    PopupDialogCfg3& setDetailInstructions(const wxString& label) { pdCfg.setDetailInstructions(label); return *this; } //
-    PopupDialogCfg3& setCheckBox(bool& value, const wxString& label) { pdCfg.setCheckBox(value, label); return *this; }
+    PopupDialogCfg3& setIcon              (const wxBitmap& bmp  ) { pdCfg_.setIcon              (bmp);   return *this; }
+    PopupDialogCfg3& setTitle             (const wxString& label) { pdCfg_.setTitle             (label); return *this; }
+    PopupDialogCfg3& setMainInstructions  (const wxString& label) { pdCfg_.setMainInstructions  (label); return *this; } //set at least one of these!
+    PopupDialogCfg3& setDetailInstructions(const wxString& label) { pdCfg_.setDetailInstructions(label); return *this; } //
+    PopupDialogCfg3& setCheckBox(bool& value, const wxString& label) { pdCfg_.setCheckBox(value, label); return *this; }
     PopupDialogCfg3& setCheckBox(bool& value, const wxString& label, ConfirmationButton3 disableWhenChecked)
     {
         assert(disableWhenChecked != ConfirmationButton3::CANCEL);
         setCheckBox(value, label);
-        buttonToDisableWhenChecked = disableWhenChecked;
+        buttonToDisableWhenChecked_ = disableWhenChecked;
         return *this;
     }
 
 private:
     friend class ConfirmationDialog3;
 
-    PopupDialogCfg pdCfg;
-    ConfirmationButton3 buttonToDisableWhenChecked = ConfirmationButton3::CANCEL;
+    PopupDialogCfg pdCfg_;
+    ConfirmationButton3 buttonToDisableWhenChecked_ = ConfirmationButton3::CANCEL;
 };
 }
 
diff --git a/wx+/popup_dlg_generated.cpp b/wx+/popup_dlg_generated.cpp
index b726aa9a..6df18dce 100644
--- a/wx+/popup_dlg_generated.cpp
+++ b/wx+/popup_dlg_generated.cpp
@@ -34,7 +34,10 @@ PopupDialogGenerated::PopupDialogGenerated( wxWindow* parent, wxWindowID id, con
 
     m_staticTextMain = new wxStaticText( m_panel33, wxID_ANY, _("dummy"), wxDefaultPosition, wxDefaultSize, 0 );
     m_staticTextMain->Wrap( -1 );
-    bSizer16->Add( m_staticTextMain, 0, wxTOP|wxBOTTOM|wxRIGHT, 5 );
+    bSizer16->Add( m_staticTextMain, 0, wxRIGHT, 10 );
+
+
+    bSizer16->Add( 0, 5, 0, 0, 5 );
 
     m_textCtrlTextDetail = new wxTextCtrl( m_panel33, wxID_ANY, wxEmptyString, wxDefaultPosition, wxDefaultSize, wxTE_MULTILINE|wxTE_READONLY|wxNO_BORDER );
     bSizer16->Add( m_textCtrlTextDetail, 1, wxEXPAND, 5 );
diff --git a/wx+/std_button_layout.h b/wx+/std_button_layout.h
index 59fda260..3e335882 100644
--- a/wx+/std_button_layout.h
+++ b/wx+/std_button_layout.h
@@ -16,14 +16,13 @@ namespace zen
 {
 struct StdButtons
 {
-    StdButtons() : btnYes(nullptr), btnNo(nullptr), btnCancel(nullptr) {}
     StdButtons& setAffirmative (wxButton* btn) { btnYes    = btn; return *this; }
     StdButtons& setNegative    (wxButton* btn) { btnNo     = btn; return *this; }
     StdButtons& setCancel      (wxButton* btn) { btnCancel = btn; return *this; }
 
-    wxButton* btnYes;
-    wxButton* btnNo;
-    wxButton* btnCancel;
+    wxButton* btnYes    = nullptr;
+    wxButton* btnNo     = nullptr;
+    wxButton* btnCancel = nullptr;
 };
 
 void setStandardButtonLayout(wxBoxSizer& sizer, const StdButtons& buttons = StdButtons());
diff --git a/wx+/tooltip.cpp b/wx+/tooltip.cpp
index c2c562ce..8dc79d73 100644
--- a/wx+/tooltip.cpp
+++ b/wx+/tooltip.cpp
@@ -16,15 +16,15 @@
 using namespace zen;
 
 
-class Tooltip::TooltipDialogGenerated : public wxDialog
+class Tooltip::TooltipDlgGenerated : public wxDialog
 {
 public:
-    TooltipDialogGenerated(wxWindow* parent,
-                           wxWindowID id = wxID_ANY,
-                           const wxString& title = {},
-                           const wxPoint& pos = wxDefaultPosition,
-                           const wxSize& size = wxDefaultSize,
-                           long style = 0) : wxDialog(parent, id, title, pos, size, style)
+    TooltipDlgGenerated(wxWindow* parent,
+                        wxWindowID id = wxID_ANY,
+                        const wxString& title = {},
+                        const wxPoint& pos = wxDefaultPosition,
+                        const wxSize& size = wxDefaultSize,
+                        long style = 0) : wxDialog(parent, id, title, pos, size, style)
     {
         //Suse Linux/X11: needs parent window, else there are z-order issues
 
@@ -33,11 +33,11 @@ public:
         this->SetForegroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_INFOTEXT)); //
 
         wxBoxSizer* bSizer158 = new wxBoxSizer(wxHORIZONTAL);
-        m_bitmapLeft = new wxStaticBitmap(this, wxID_ANY, wxNullBitmap, wxDefaultPosition, wxDefaultSize, 0);
-        bSizer158->Add(m_bitmapLeft, 0, wxALL | wxALIGN_CENTER_VERTICAL, 5);
+        bitmapLeft_ = new wxStaticBitmap(this, wxID_ANY, wxNullBitmap, wxDefaultPosition, wxDefaultSize, 0);
+        bSizer158->Add(bitmapLeft_, 0, wxALL | wxALIGN_CENTER_VERTICAL, 5);
 
-        m_staticTextMain = new wxStaticText(this, wxID_ANY, wxString(), wxDefaultPosition, wxDefaultSize, 0);
-        bSizer158->Add(m_staticTextMain, 0, wxALL | wxALIGN_CENTER_HORIZONTAL | wxALIGN_CENTER_VERTICAL, 5);
+        staticTextMain_ = new wxStaticText(this, wxID_ANY, wxString(), wxDefaultPosition, wxDefaultSize, 0);
+        bSizer158->Add(staticTextMain_, 0, wxALL | wxALIGN_CENTER_HORIZONTAL | wxALIGN_CENTER_VERTICAL, 5);
 
         this->SetSizer(bSizer158);
         this->Layout();
@@ -48,57 +48,57 @@ public:
 #endif
     }
 
-    wxStaticText* m_staticTextMain;
-    wxStaticBitmap* m_bitmapLeft;
+    wxStaticText* staticTextMain_;
+    wxStaticBitmap* bitmapLeft_;
 };
 
 
 void Tooltip::show(const wxString& text, wxPoint mousePos, const wxBitmap* bmp)
 {
-    if (!tipWindow)
-        tipWindow = new TooltipDialogGenerated(&parent_); //ownership passed to parent
+    if (!tipWindow_)
+        tipWindow_ = new TooltipDlgGenerated(&parent_); //ownership passed to parent
 
     const wxBitmap& newBmp = bmp ? *bmp : wxNullBitmap;
 
-    if (!isEqual(tipWindow->m_bitmapLeft->GetBitmap(), newBmp))
+    if (!isEqual(tipWindow_->bitmapLeft_->GetBitmap(), newBmp))
     {
-        tipWindow->m_bitmapLeft->SetBitmap(newBmp);
-        tipWindow->Refresh(); //needed if bitmap size changed!
+        tipWindow_->bitmapLeft_->SetBitmap(newBmp);
+        tipWindow_->Refresh(); //needed if bitmap size changed!
     }
 
-    if (text != tipWindow->m_staticTextMain->GetLabel())
+    if (text != tipWindow_->staticTextMain_->GetLabel())
     {
-        tipWindow->m_staticTextMain->SetLabel(text);
-        tipWindow->m_staticTextMain->Wrap(600);
+        tipWindow_->staticTextMain_->SetLabel(text);
+        tipWindow_->staticTextMain_->Wrap(600);
     }
 
-    tipWindow->GetSizer()->SetSizeHints(tipWindow); //~=Fit() + SetMinSize()
+    tipWindow_->GetSizer()->SetSizeHints(tipWindow_); //~=Fit() + SetMinSize()
     //Linux: Fit() seems to be broken => this needs to be called EVERY time inside show, not only if text or bmp change
 
     const wxPoint newPos = wxTheApp->GetLayoutDirection() == wxLayout_RightToLeft ?
-                           mousePos - wxPoint(30 + tipWindow->GetSize().GetWidth(), 0) :
+                           mousePos - wxPoint(30 + tipWindow_->GetSize().GetWidth(), 0) :
                            mousePos + wxPoint(30, 0);
 
-    if (newPos != tipWindow->GetScreenPosition())
-        tipWindow->SetSize(newPos.x, newPos.y, wxDefaultCoord, wxDefaultCoord);
+    if (newPos != tipWindow_->GetScreenPosition())
+        tipWindow_->SetSize(newPos.x, newPos.y, wxDefaultCoord, wxDefaultCoord);
     //attention!!! possible endless loop: mouse pointer must NOT be within tipWindow!
     //else it will trigger a wxEVT_LEAVE_WINDOW on middle grid which will hide the window, causing the window to be shown again via this method, etc.
 
-    if (!tipWindow->IsShown())
-        tipWindow->Show();
+    if (!tipWindow_->IsShown())
+        tipWindow_->Show();
 }
 
 
 void Tooltip::hide()
 {
-    if (tipWindow)
+    if (tipWindow_)
     {
 #ifdef ZEN_LINUX
         //on wxGTK the tooltip is sometimes not shown again after it was hidden: e.g. drag-selection on middle grid
-        tipWindow->Destroy(); //apply brute force:
-        tipWindow = nullptr;  //
+        tipWindow_->Destroy(); //apply brute force:
+        tipWindow_ = nullptr;  //
 #else
-        tipWindow->Hide();
+        tipWindow_->Hide();
 #endif
     }
 }
diff --git a/wx+/tooltip.h b/wx+/tooltip.h
index 23c7adb1..f2a7043e 100644
--- a/wx+/tooltip.h
+++ b/wx+/tooltip.h
@@ -23,8 +23,8 @@ public:
     void hide();
 
 private:
-    class TooltipDialogGenerated;
-    TooltipDialogGenerated* tipWindow = nullptr;
+    class TooltipDlgGenerated;
+    TooltipDlgGenerated* tipWindow_ = nullptr;
     wxWindow& parent_;
 };
 }
diff --git a/zen/basic_math.h b/zen/basic_math.h
index e9e17466..eed23477 100644
--- a/zen/basic_math.h
+++ b/zen/basic_math.h
@@ -18,7 +18,7 @@
 namespace numeric
 {
 template <class T> T abs(T value);
-template <class T> T dist(T a, T b);
+template <class T> auto dist(T a, T b);
 template <class T> int sign(T value); //returns one of {-1, 0, 1}
 template <class T> T min(T a, T b, T c);
 template <class T> T max(T a, T b, T c);
@@ -90,7 +90,7 @@ T abs(T value)
 }
 
 template <class T> inline
-T dist(T a, T b)
+auto dist(T a, T b) //return type might be different than T, e.g. std::chrono::duration instead of std::chrono::time_point
 {
     return a > b ? a - b : b - a;
 }
diff --git a/zen/crc.h b/zen/crc.h
index b617bdd0..5c950efc 100644
--- a/zen/crc.h
+++ b/zen/crc.h
@@ -19,6 +19,19 @@
 
 namespace zen
 {
+uint16_t getCrc16(const std::string& str);
+uint32_t getCrc32(const std::string& str);
+template <class ByteIterator> uint16_t getCrc16(ByteIterator first, ByteIterator last);
+template <class ByteIterator> uint32_t getCrc32(ByteIterator first, ByteIterator last);
+
+
+
+
+//------------------------- implementation -------------------------------
+inline uint16_t getCrc16(const std::string& str) { return getCrc16(str.begin(), str.end()); }
+inline uint32_t getCrc32(const std::string& str) { return getCrc32(str.begin(), str.end()); }
+
+
 template <class ByteIterator> inline
 uint16_t getCrc16(ByteIterator first, ByteIterator last)
 {
diff --git a/zen/dir_watcher.cpp b/zen/dir_watcher.cpp
index 12a6a9f4..98190bba 100644
--- a/zen/dir_watcher.cpp
+++ b/zen/dir_watcher.cpp
@@ -9,6 +9,7 @@
 #include <set>
 #include "thread.h"
 #include "scope_guard.h"
+#include "basic_math.h"
 
 #ifdef ZEN_WIN
     #include "device_notify.h"
@@ -358,10 +359,11 @@ std::vector<DirWatcher::Entry> DirWatcher::getChanges(const std::function<void()
     //wait until device removal is confirmed, to prevent locking hDir again by some new watch!
     if (pimpl_->volRemoval->requestReceived())
     {
-        const std::chrono::steady_clock::time_point stopTime = std::chrono::steady_clock::now() + std::chrono::seconds(15);
+        const auto startTime = std::chrono::steady_clock::now();
         //HandleVolumeRemoval::finished() not guaranteed! note: Windows gives unresponsive applications ca. 10 seconds until unmounting the usb stick in worst case
 
-        while (!pimpl_->volRemoval->finished() && std::chrono::steady_clock::now() < stopTime)
+        while (!pimpl_->volRemoval->finished() &&
+               numeric::dist(std::chrono::steady_clock::now(), startTime) < std::chrono::seconds(15)) //handle potential chrono wrap-around!
         {
             processGuiMessages(); //DBT_DEVICEREMOVECOMPLETE message is sent here!
             std::this_thread::sleep_for(std::chrono::milliseconds(50));
diff --git a/zen/file_traverser.cpp b/zen/file_traverser.cpp
index b4599d03..3eb284e1 100644
--- a/zen/file_traverser.cpp
+++ b/zen/file_traverser.cpp
@@ -62,7 +62,7 @@ void zen::traverseFolder(const Zstring& dirPath,
                 if (ec == ERROR_NO_MORE_FILES) //not an error situation
                     return;
                 //else we have a problem... report it:
-                throw FileError(replaceCpy(_("Cannot enumerate directory %x."), L"%x", fmtPath(dirPath)), formatSystemError(L"FindNextFile", ec));
+                throw FileError(replaceCpy(_("Cannot read directory %x."), L"%x", fmtPath(dirPath)), formatSystemError(L"FindNextFile", ec));
             }
 
             //skip "." and ".."
@@ -73,7 +73,7 @@ void zen::traverseFolder(const Zstring& dirPath,
                 continue;
 
             if (itemNameRaw[0] == 0)
-                throw FileError(replaceCpy(_("Cannot enumerate directory %x."), L"%x", fmtPath(dirPath)), L"FindNextFile: Data corruption; item with empty name.");
+                throw FileError(replaceCpy(_("Cannot read directory %x."), L"%x", fmtPath(dirPath)), L"FindNextFile: Data corruption; item with empty name.");
 
             const Zstring& itemPath = appendSeparator(dirPath) + itemNameRaw;
 
@@ -112,7 +112,7 @@ void zen::traverseFolder(const Zstring& dirPath,
         {
             struct ::dirent* dirEntry = nullptr;
             if (::readdir_r(folder, reinterpret_cast< ::dirent*>(&buffer[0]), &dirEntry) != 0)
-                THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot enumerate directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r");
+                THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r");
             //don't retry but restart dir traversal on error! https://blogs.msdn.microsoft.com/oldnewthing/20140612-00/?p=753/
 
             if (!dirEntry) //no more items
@@ -133,14 +133,14 @@ void zen::traverseFolder(const Zstring& dirPath,
             }
             catch (const SysError& e) //failure is not an item-level error since we don't know the normalized name yet!!!
             {
-                throw FileError(replaceCpy(_("Cannot enumerate directory %x."), L"%x", fmtPath(dirPath)),
+                throw FileError(replaceCpy(_("Cannot read directory %x."), L"%x", fmtPath(dirPath)),
                                 L"Failed to generate normalized file name: " + fmtPath(itemNameRaw) + L"\n" + e.toString()); //too obscure to warrant translation
             }
 #else
             const Zstring& itemName = itemNameRaw;
 #endif
             if (itemName.empty()) //checks result of osx::normalizeUtfForPosix, too!
-                throw FileError(replaceCpy(_("Cannot enumerate directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r: Data corruption; item with empty name.");
+                throw FileError(replaceCpy(_("Cannot read directory %x."), L"%x", fmtPath(dirPath)), L"readdir_r: Data corruption; item with empty name.");
 
             const Zstring& itemPath = appendSeparator(dirPath) + itemName;
 
diff --git a/zen/fixed_list.h b/zen/fixed_list.h
index 4376c13f..81197eb4 100644
--- a/zen/fixed_list.h
+++ b/zen/fixed_list.h
@@ -15,7 +15,7 @@ namespace zen
 {
 //std::list(C++11)-like class for inplace element construction supporting non-copyable/non-movable types
 //-> no iterator invalidation after emplace_back()
-	
+
 template <class T>
 class FixedList
 {
@@ -69,7 +69,7 @@ public:
     const_reference& back() const { return lastInsert_->val; }
 
     template <class... Args>
-    void emplace_back(Args&&... args)
+    void emplace_back(Args&& ... args)
     {
         Node* newNode = new Node(std::forward<Args>(args)...);
 
@@ -160,10 +160,10 @@ class FixedVector
 public:
     FixedVector() {}
 
-	/*
-	class EndIterator {}; //just like FixedList: no iterator invalidation after emplace_back()
+    /*
+    class EndIterator {}; //just like FixedList: no iterator invalidation after emplace_back()
 
-	template <class V>
+    template <class V>
     class FixedIterator : public std::iterator<std::forward_iterator_tag, V> //could make this random-access if needed
     {
     public:
@@ -174,10 +174,10 @@ public:
         V& operator* () const { return  *cont_[pos_]; }
         V* operator->() const { return &*cont_[pos_]; }
     private:
-		std::vector<std::unique_ptr<T>>& cont_;
-		size_t pos_ = 0; 
+        std::vector<std::unique_ptr<T>>& cont_;
+        size_t pos_ = 0;
     };
-	*/
+    */
 
     template <class IterImpl, class V>
     class FixedIterator : public std::iterator<std::forward_iterator_tag, V> //could make this bidirectional if needed
@@ -188,7 +188,7 @@ public:
         inline friend bool operator==(const FixedIterator& lhs, const FixedIterator& rhs) { return lhs.it_ == rhs.it_; }
         inline friend bool operator!=(const FixedIterator& lhs, const FixedIterator& rhs) { return !(lhs == rhs); }
         V& operator* () const { return  **it_; }
-        V* operator->() const { return &**it_; }
+        V* operator->() const { return &** it_; }
     private:
         IterImpl it_;  //TODO: avoid iterator invalidation after emplace_back(); caveat: end() must not store old length!
     };
@@ -199,10 +199,10 @@ public:
     using reference       =       T&;
     using const_reference = const T&;
 
-	iterator begin() { return items_.begin(); }
+    iterator begin() { return items_.begin(); }
     iterator end  () { return items_.end  (); }
 
-	const_iterator begin() const { return items_.begin(); }
+    const_iterator begin() const { return items_.begin(); }
     const_iterator end  () const { return items_.end  (); }
 
     reference       front()       { return *items_.front(); }
@@ -212,15 +212,15 @@ public:
     const_reference& back() const { return *items_.back(); }
 
     template <class... Args>
-    void emplace_back(Args&&... args)
+    void emplace_back(Args&& ... args)
     {
-		items_.push_back(std::make_unique<T>(std::forward<Args>(args)...));
+        items_.push_back(std::make_unique<T>(std::forward<Args>(args)...));
     }
 
     template <class Predicate>
     void remove_if(Predicate pred)
     {
-		erase_if(items_, [&](const std::unique_ptr<T>& p){ return pred(*p); });
+        erase_if(items_, [&](const std::unique_ptr<T>& p) { return pred(*p); });
     }
 
     void   clear() { items_.clear(); }
@@ -232,7 +232,7 @@ private:
     FixedVector           (const FixedVector&) = delete;
     FixedVector& operator=(const FixedVector&) = delete;
 
-	std::vector<std::unique_ptr<T>> items_;
+    std::vector<std::unique_ptr<T>> items_;
 };
 }
 
diff --git a/zen/format_unit.cpp b/zen/format_unit.cpp
index d87a1643..08463778 100644
--- a/zen/format_unit.cpp
+++ b/zen/format_unit.cpp
@@ -16,7 +16,7 @@
 #ifdef ZEN_WIN
     #include "int64.h"
     #include "win.h" //includes "windows.h"
-    #include "win_ver.h"
+    //    #include "win_ver.h"
 
 #elif defined ZEN_LINUX || defined ZEN_MAC
     #include <clocale> //thousands separator
@@ -155,6 +155,12 @@ std::wstring zen::remainingTimeToString(double timeInSec)
 }
 
 
+//std::wstring zen::fractionToString1Dec(double fraction)
+//{
+//    return printNumber<std::wstring>(L"%.1f", fraction * 100.0) + L'%'; //no need to internationalize fraction!?
+//}
+
+
 std::wstring zen::fractionToString(double fraction)
 {
     return printNumber<std::wstring>(L"%.2f", fraction * 100.0) + L'%'; //no need to internationalize fraction!?
@@ -299,32 +305,29 @@ std::wstring zen::utcToLocalTimeString(std::int64_t utcTime)
 
     SYSTEMTIME systemTimeLocal = {};
 
-    static const bool useNewLocalTimeCalculation = zen::vistaOrLater();
-
     //https://msdn.microsoft.com/en-us/library/ms724277
-    if (useNewLocalTimeCalculation) //DST conversion  like in Windows 7: NTFS stays fixed, but FAT jumps by one hour
-    {
-        SYSTEMTIME systemTimeUtc = {};
-        if (!::FileTimeToSystemTime(&lastWriteTimeUtc, //__in   const FILETIME *lpFileTime,
-                                    &systemTimeUtc))   //__out  LPSYSTEMTIME lpSystemTime
-            return errorMsg();
-
-        if (!::SystemTimeToTzSpecificLocalTime(nullptr,           //__in_opt  LPTIME_ZONE_INFORMATION lpTimeZone,
-                                               &systemTimeUtc,    //__in      LPSYSTEMTIME lpUniversalTime,
-                                               &systemTimeLocal)) //__out     LPSYSTEMTIME lpLocalTime
-            return errorMsg();
-    }
-    else //DST conversion like in Windows 2000 and XP: FAT times stay fixed, while NTFS jumps
-    {
-        FILETIME fileTimeLocal = {};
-        if (!::FileTimeToLocalFileTime(&lastWriteTimeUtc, //_In_   const FILETIME *lpFileTime,
-                                       &fileTimeLocal))   //_Out_  LPFILETIME lpLocalFileTime
-            return errorMsg();
-
-        if (!::FileTimeToSystemTime(&fileTimeLocal,    //__in   const FILETIME *lpFileTime,
-                                    &systemTimeLocal)) //__out  LPSYSTEMTIME lpSystemTime
-            return errorMsg();
-    }
+#ifdef ZEN_WIN_VISTA_AND_LATER
+    //DST conversion  like in Vista and later: NTFS stays fixed, but FAT jumps by one hour
+    SYSTEMTIME systemTimeUtc = {};
+    if (!::FileTimeToSystemTime(&lastWriteTimeUtc, //__in   const FILETIME *lpFileTime,
+                                &systemTimeUtc))   //__out  LPSYSTEMTIME lpSystemTime
+        return errorMsg();
+
+    if (!::SystemTimeToTzSpecificLocalTime(nullptr,           //__in_opt  LPTIME_ZONE_INFORMATION lpTimeZone,
+                                           &systemTimeUtc,    //__in      LPSYSTEMTIME lpUniversalTime,
+                                           &systemTimeLocal)) //__out     LPSYSTEMTIME lpLocalTime
+        return errorMsg();
+#else
+    //DST conversion like in Windows 2000 and XP: FAT times stay fixed, while NTFS jumps
+    FILETIME fileTimeLocal = {};
+    if (!::FileTimeToLocalFileTime(&lastWriteTimeUtc, //_In_   const FILETIME *lpFileTime,
+                                   &fileTimeLocal))   //_Out_  LPFILETIME lpLocalFileTime
+        return errorMsg();
+
+    if (!::FileTimeToSystemTime(&fileTimeLocal,    //__in   const FILETIME *lpFileTime,
+                                &systemTimeLocal)) //__out  LPSYSTEMTIME lpSystemTime
+        return errorMsg();
+#endif
 
     zen::TimeComp loc;
     loc.year   = systemTimeLocal.wYear;
diff --git a/zen/i18n.h b/zen/i18n.h
index 4f62fd4c..e5b0ab2c 100644
--- a/zen/i18n.h
+++ b/zen/i18n.h
@@ -98,7 +98,7 @@ std::wstring translate(const std::wstring& singular, const std::wstring& plural,
 
 
 inline
-Global<const TranslationHandler>& getGlobalTranslationHandler()
+Global<const TranslationHandler>& refGlobalTranslationHandler()
 {
     //getTranslator() may be called even after static objects of this translation unit are destroyed!
     static Global<const TranslationHandler> inst; //external linkage even in header!
@@ -110,14 +110,14 @@ Global<const TranslationHandler>& getGlobalTranslationHandler()
 inline
 void setTranslator(std::unique_ptr<const TranslationHandler>&& newHandler)
 {
-    implementation::getGlobalTranslationHandler().set(std::move(newHandler));
+    implementation::refGlobalTranslationHandler().set(std::move(newHandler));
 }
 
 
 inline
 std::shared_ptr<const TranslationHandler> getTranslator()
 {
-    return implementation::getGlobalTranslationHandler().get();
+    return implementation::refGlobalTranslationHandler().get();
 }
 }
 
diff --git a/zen/perf.h b/zen/perf.h
index e3827fd1..6cd874b8 100644
--- a/zen/perf.h
+++ b/zen/perf.h
@@ -7,12 +7,13 @@
 #ifndef PERF_H_83947184145342652456
 #define PERF_H_83947184145342652456
 
+#include <chrono>
 #include "deprecate.h"
-#include "tick_count.h"
 #include "scope_guard.h"
 
 #ifdef ZEN_WIN
     #include <sstream>
+    #include "win.h"
 #else
     #include <iostream>
 #endif
@@ -28,54 +29,47 @@ namespace zen
 class PerfTimer
 {
 public:
-    class TimerError {};
+    ZEN_DEPRECATE PerfTimer() {}
 
-    ZEN_DEPRECATE
-    PerfTimer() : startTime(getTicksNow()) //throw TimerError
-    {
-        //std::clock() - "counts CPU time in Linux GCC and wall time in VC++" - WTF!???
-        if (ticksPerSec_ == 0)
-            throw TimerError();
-    }
-
-    ~PerfTimer() { if (!resultShown) try { showResult(); } catch (TimerError&) { assert(false); } }
+    ~PerfTimer() { if (!resultShown_) showResult(); }
 
     void pause()
     {
-        if (!paused)
+        if (!paused_)
         {
-            paused = true;
-            elapsedUntilPause += dist(startTime, getTicksNow());
+            paused_ = true;
+            elapsedUntilPause_ += std::chrono::steady_clock::now() - startTime_; //ignore potential ::QueryPerformanceCounter() wrap-around!
         }
     }
 
     void resume()
     {
-        if (paused)
+        if (paused_)
         {
-            paused = false;
-            startTime = getTicksNow();
+            paused_ = false;
+            startTime_ = std::chrono::steady_clock::now();
         }
     }
 
     void restart()
     {
-        startTime = getTicksNow();
-        paused = false;
-        elapsedUntilPause = 0;
+        paused_ = false;
+        startTime_ = std::chrono::steady_clock::now();
+        elapsedUntilPause_ = std::chrono::nanoseconds::zero();
     }
 
     int64_t timeMs() const
     {
-        int64_t ticksTotal = elapsedUntilPause;
-        if (!paused)
-            ticksTotal += dist(startTime, getTicksNow());
-        return 1000 * ticksTotal / ticksPerSec_;
+        auto elapsedTotal = elapsedUntilPause_;
+        if (!paused_)
+            elapsedTotal += std::chrono::steady_clock::now() - startTime_;
+
+        return std::chrono::duration_cast<std::chrono::milliseconds>(elapsedTotal).count();
     }
 
     void showResult()
     {
-        const bool wasRunning = !paused;
+        const bool wasRunning = !paused_;
         if (wasRunning) pause(); //don't include call to MessageBox()!
         ZEN_ON_SCOPE_EXIT(if (wasRunning) resume());
 
@@ -86,23 +80,14 @@ public:
 #else
         std::clog << "Perf: duration: " << timeMs() << " ms\n";
 #endif
-        resultShown = true;
+        resultShown_ = true;
     }
 
 private:
-    TickVal getTicksNow() const
-    {
-        const TickVal now = getTicks();
-        if (!now.isValid())
-            throw TimerError();
-        return now;
-    }
-
-    const std::int64_t ticksPerSec_ = ticksPerSec(); //return 0 on error
-    bool resultShown = false;
-    TickVal startTime;
-    bool paused = false;
-    int64_t elapsedUntilPause = 0;
+    bool resultShown_ = false;
+    bool paused_      = false;
+    std::chrono::steady_clock::time_point startTime_ = std::chrono::steady_clock::now(); //uses ::QueryPerformanceCounter()
+    std::chrono::nanoseconds elapsedUntilPause_{}; //std::chrono::duration is uninitialized by default! WTF! When will this stupidity end???
 };
 }
 
diff --git a/zen/serialize.h b/zen/serialize.h
index bc047fee..7322cb07 100644
--- a/zen/serialize.h
+++ b/zen/serialize.h
@@ -72,8 +72,8 @@ struct UnbufferedOutputStream
     size_t tryWrite(const void* buffer, size_t bytesToWrite); //may return short! CONTRACT: bytesToWrite > 0
 };
 */
-//functions based on unbuffered stream abstraction
 
+//functions based on unbuffered stream abstraction
 template <class UnbufferedInputStream, class UnbufferedOutputStream>
 void unbufferedStreamCopy(UnbufferedInputStream& streamIn, UnbufferedOutputStream& streamOut, const std::function<void(std::int64_t bytesDelta)>& notifyProgress); //throw X
 
@@ -104,7 +104,6 @@ struct BufferedOutputStream
 template <class N, class BufferedOutputStream> void writeNumber   (BufferedOutputStream& stream, const N& num);                 //
 template <class C, class BufferedOutputStream> void writeContainer(BufferedOutputStream& stream, const C& str);                 //throw ()
 template <         class BufferedOutputStream> void writeArray    (BufferedOutputStream& stream, const void* data, size_t len); //
-
 //----------------------------------------------------------------------
 class UnexpectedEndOfStreamError {};
 template <class N, class BufferedInputStream> N    readNumber   (BufferedInputStream& stream); //throw UnexpectedEndOfStreamError (corrupted data)
@@ -115,21 +114,23 @@ template <         class BufferedInputStream> void readArray    (BufferedInputSt
 template <class BinContainer>
 struct MemoryStreamIn
 {
-    MemoryStreamIn(const BinContainer& cont) : buffer(cont) {} //this better be cheap!
+    MemoryStreamIn(const BinContainer& cont) : buffer_(cont) {} //this better be cheap!
 
     size_t read(void* data, size_t len) //return "len" bytes unless end of stream!
     {
         static_assert(sizeof(typename BinContainer::value_type) == 1, ""); //expect: bytes
-        const size_t bytesRead = std::min(len, buffer.size() - pos);
-        auto itFirst = buffer.begin() + pos;
+        const size_t bytesRead = std::min(len, buffer_.size() - pos_);
+        auto itFirst = buffer_.begin() + pos_;
         std::copy(itFirst, itFirst + bytesRead, static_cast<char*>(data));
-        pos += bytesRead;
+        pos_ += bytesRead;
         return bytesRead;
     }
 
+	size_t pos() const { return pos_; }
+
 private:
-    const BinContainer buffer;
-    size_t pos = 0;
+    const BinContainer buffer_;
+    size_t pos_ = 0;
 };
 
 template <class BinContainer>
@@ -138,15 +139,15 @@ struct MemoryStreamOut
     void write(const void* data, size_t len)
     {
         static_assert(sizeof(typename BinContainer::value_type) == 1, ""); //expect: bytes
-        const size_t oldSize = buffer.size();
-        buffer.resize(oldSize + len);
-        std::copy(static_cast<const char*>(data), static_cast<const char*>(data) + len, buffer.begin() + oldSize);
+        const size_t oldSize = buffer_.size();
+        buffer_.resize(oldSize + len);
+        std::copy(static_cast<const char*>(data), static_cast<const char*>(data) + len, buffer_.begin() + oldSize);
     }
 
-    const BinContainer& ref() const { return buffer; }
+    const BinContainer& ref() const { return buffer_; }
 
 private:
-    BinContainer buffer;
+    BinContainer buffer_;
 };
 
 
diff --git a/zen/shell_execute.h b/zen/shell_execute.h
index ee8203c3..2f73fc38 100644
--- a/zen/shell_execute.h
+++ b/zen/shell_execute.h
@@ -38,7 +38,7 @@ bool shellExecuteImpl(Function fillExecInfo, ExecutionType type)
     SHELLEXECUTEINFO execInfo = {};
     execInfo.cbSize = sizeof(execInfo);
     execInfo.lpVerb = nullptr;
-    execInfo.nShow  = SW_SHOWNORMAL;
+    execInfo.nShow  = SW_SHOW;
     execInfo.fMask  = type == EXEC_TYPE_SYNC ? (SEE_MASK_NOCLOSEPROCESS | SEE_MASK_NOASYNC) : 0;
     //don't use SEE_MASK_ASYNCOK -> different async mode than the default which returns successful despite errors!
     execInfo.fMask |= SEE_MASK_FLAG_NO_UI; //::ShellExecuteEx() shows a non-blocking pop-up dialog on errors -> we want a blocking one
@@ -98,7 +98,7 @@ void shellExecute(const Zstring& command, ExecutionType type) //throw FileError
     {
         filePath = argv[0];
         for (auto it = argv.begin() + 1; it != argv.end(); ++it)
-            arguments += (it != argv.begin() ? L" " : L"") +
+            arguments += (it == argv.begin() + 1 ? L"" : L" ") +
                          (it->empty() || std::any_of(it->begin(), it->end(), &isWhiteSpace<wchar_t>) ? L"\"" + *it + L"\"" : *it);
     }
 
diff --git a/zen/stl_tools.h b/zen/stl_tools.h
index 064d5b51..48f475f3 100644
--- a/zen/stl_tools.h
+++ b/zen/stl_tools.h
@@ -235,7 +235,7 @@ size_t hashBytesAppend(size_t hashVal, ByteIterator first, ByteIterator last)
 #endif
     static_assert(sizeof(typename std::iterator_traits<ByteIterator>::value_type) == 1, "");
 
-	for (; first != last; ++first)
+    for (; first != last; ++first)
     {
         hashVal ^= static_cast<size_t>(*first);
         hashVal *= prime;
diff --git a/zen/string_tools.h b/zen/string_tools.h
index 9b8e7328..5292dfc6 100644
--- a/zen/string_tools.h
+++ b/zen/string_tools.h
@@ -24,6 +24,7 @@ namespace zen
 {
 template <class Char> bool isWhiteSpace(Char ch);
 template <class Char> bool isDigit     (Char ch); //not exactly the same as "std::isdigit" -> we consider '0'-'9' only!
+template <class Char> bool isHexDigit  (Char ch);
 template <class Char> bool isAlpha     (Char ch);
 
 template <class S, class T> bool startsWith(const S& str, const T& prefix);  //
@@ -51,6 +52,9 @@ template <class S, class T, class U> S    replaceCpy(const S& str, const T& oldT
 template <class S,   class Num> S   numberTo(const Num& number);
 template <class Num, class S  > Num stringTo(const S&   str);
 
+std::pair<char, char> hexify  (unsigned char c, bool upperCase = true);
+char                  unhexify(char high, char low);
+
 template <class S, class T, class Num> S printNumber(const T& format, const Num& number); //format a single number using std::snprintf()
 
 //string to string conversion: converts string-like type into char-compatible target string class
@@ -101,6 +105,16 @@ bool isDigit(Char ch) //similar to implmenetation of std::::isdigit()!
 }
 
 
+template <class Char> inline
+bool isHexDigit(Char c)
+{
+    static_assert(IsSameType<Char, char>::value || IsSameType<Char, wchar_t>::value, "");
+    return (static_cast<Char>('0') <= c && c <= static_cast<Char>('9')) ||
+           (static_cast<Char>('A') <= c && c <= static_cast<Char>('F')) ||
+           (static_cast<Char>('a') <= c && c <= static_cast<Char>('f'));
+}
+
+
 template <> bool isAlpha(char ch) = delete; //probably not a good idea with UTF-8 anyway...
 
 template <> inline bool isAlpha(wchar_t ch) { return std::iswalpha(ch) != 0; }
@@ -297,7 +311,7 @@ S replaceCpy(const S& str, const T& oldTerm, const U& newTerm, bool replaceAll)
         return str;
 
     const auto* const newBegin = strBegin(newTerm);
-	const auto* const newEnd   = newBegin + strLength(newTerm);
+    const auto* const newEnd   = newBegin + strLength(newTerm);
     S output;
 
     for (;;)
@@ -658,6 +672,42 @@ Num stringTo(const S& str)
 
     return impl::stringTo<Num>(str, TypeTag());
 }
+
+
+inline //hexify beats "printNumber<std::string>("%02X", c)" by a nice factor of 3!
+std::pair<char, char> hexify(unsigned char c, bool upperCase)
+{
+    auto hexifyDigit = [upperCase](int num) -> char //input [0, 15], output 0-9, A-F
+    {
+        assert(0 <= num&& num <= 15);  //guaranteed by design below!
+        if (num <= 9)
+            return static_cast<char>('0' + num); //no signed/unsigned char problem here!
+
+        if (upperCase)
+            return static_cast<char>('A' + (num - 10));
+        else
+            return static_cast<char>('a' + (num - 10));
+    };
+    return std::make_pair(hexifyDigit(c / 16), hexifyDigit(c % 16));
+}
+
+
+inline //unhexify beats "::sscanf(&it[3], "%02X", &tmp)" by a factor of 3000 for ~250000 calls!!!
+char unhexify(char high, char low)
+{
+    auto unhexifyDigit = [](char hex) -> int //input 0-9, a-f, A-F; output range: [0, 15]
+    {
+        if ('0' <= hex && hex <= '9') //no signed/unsigned char problem here!
+            return hex - '0';
+        else if ('A' <= hex && hex <= 'F')
+            return (hex - 'A') + 10;
+        else if ('a' <= hex && hex <= 'f')
+            return (hex - 'a') + 10;
+        assert(false);
+        return 0;
+    };
+    return static_cast<unsigned char>(16 * unhexifyDigit(high) + unhexifyDigit(low)); //[!] convert to unsigned char first, then to char (which may be signed)
+}
 }
 
 #endif //STRING_TOOLS_H_213458973046
diff --git a/zen/thread.h b/zen/thread.h
index ac94da6a..5bb02a0e 100644
--- a/zen/thread.h
+++ b/zen/thread.h
@@ -460,9 +460,9 @@ std::uint64_t getThreadId()
     return ::GetCurrentThreadId(); //no-fail
 
 #elif defined ZEN_LINUX
-	//obviously "gettid()" is not available on Ubuntu/Debian/Suse => use the OpenSSL approach:
-	static_assert(sizeof(std::uint64_t) >= sizeof(void*), "");
-	return reinterpret_cast<std::uint64_t>(static_cast<void*>(&errno));
+    //obviously "gettid()" is not available on Ubuntu/Debian/Suse => use the OpenSSL approach:
+    static_assert(sizeof(std::uint64_t) >= sizeof(void*), "");
+    return reinterpret_cast<std::uint64_t>(static_cast<void*>(&errno));
 
 #elif defined ZEN_MAC
     uint64_t tid = 0;
diff --git a/zen/tick_count.h b/zen/tick_count.h
deleted file mode 100644
index 5ba4fd1b..00000000
--- a/zen/tick_count.h
+++ /dev/null
@@ -1,141 +0,0 @@
-// *****************************************************************************
-// * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
-// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
-// *****************************************************************************
-
-#ifndef TICK_COUNT_H_3807326223463457
-#define TICK_COUNT_H_3807326223463457
-
-#include <cstdint>
-#include "type_traits.h"
-#include "basic_math.h"
-
-#ifdef ZEN_WIN
-    #include "win.h" //includes "windows.h"
-#elif defined ZEN_LINUX
-    #include <time.h> //Posix ::clock_gettime()
-#elif defined ZEN_MAC
-    #include <mach/mach_time.h>
-#endif
-
-
-namespace zen
-{
-//a portable "GetTickCount()" using "wall time equivalent" - e.g. no jumps due to ntp time corrections
-class TickVal;
-int64_t dist(const TickVal& lhs, const TickVal& rhs); //use absolute difference for paranoid security: even QueryPerformanceCounter "wraps-around" at *some* time
-
-int64_t ticksPerSec(); //return 0 on error
-TickVal getTicks();    //return invalid value on error: !TickVal::isValid()
-
-
-
-
-
-
-
-
-
-//############################ implementation ##############################
-class TickVal
-{
-public:
-#ifdef ZEN_WIN
-    using NativeVal = LARGE_INTEGER;
-#elif defined ZEN_LINUX
-    using NativeVal = timespec;
-#elif defined ZEN_MAC
-    using NativeVal = uint64_t;
-#endif
-
-    TickVal() {}
-    explicit TickVal(const NativeVal& val) : val_(val) {}
-
-    inline friend
-    int64_t dist(const TickVal& lhs, const TickVal& rhs)
-    {
-#ifdef ZEN_WIN
-        return numeric::dist(lhs.val_.QuadPart, rhs.val_.QuadPart); //std::abs(a - b) can lead to overflow!
-#elif defined ZEN_LINUX
-        //structure timespec documented with members:
-        //  time_t  tv_sec    seconds
-        //  long    tv_nsec   nanoseconds
-        const int64_t deltaSec  = lhs.val_.tv_sec  - rhs.val_.tv_sec;
-        const int64_t deltaNsec = lhs.val_.tv_nsec - rhs.val_.tv_nsec;
-        return numeric::abs(deltaSec * 1000000000 + deltaNsec);
-#elif defined ZEN_MAC
-        return numeric::dist(lhs.val_, rhs.val_);
-#endif
-    }
-
-    inline friend
-    bool operator<(const TickVal& lhs, const TickVal& rhs)
-    {
-#ifdef ZEN_WIN
-        return lhs.val_.QuadPart < rhs.val_.QuadPart;
-#elif defined ZEN_LINUX
-        if (lhs.val_.tv_sec != rhs.val_.tv_sec)
-            return lhs.val_.tv_sec < rhs.val_.tv_sec;
-        return lhs.val_.tv_nsec < rhs.val_.tv_nsec;
-#elif defined ZEN_MAC
-        return lhs.val_ < rhs.val_;
-#endif
-    }
-
-    bool isValid() const { return dist(*this, TickVal()) != 0; }
-
-private:
-    NativeVal val_ {};
-};
-
-
-inline
-int64_t ticksPerSec() //return 0 on error
-{
-#ifdef ZEN_WIN
-    LARGE_INTEGER frequency = {};
-    if (!::QueryPerformanceFrequency(&frequency)) //MSDN promises: "The frequency cannot change while the system is running."
-        return 0; //MSDN: "This won't occur on any system that runs Windows XP or later."
-    static_assert(sizeof(int64_t) >= sizeof(frequency.QuadPart), "");
-    return frequency.QuadPart;
-
-#elif defined ZEN_LINUX
-    return 1000000000; //precision: nanoseconds
-
-#elif defined ZEN_MAC
-    mach_timebase_info_data_t tbi = {};
-    if (::mach_timebase_info(&tbi) != KERN_SUCCESS)
-        return 0;
-    //structure mach_timebase_info_data_t documented with members:
-    //      uint32_t    numer;
-    //      uint32_t    denom;
-    return static_cast<int64_t>(1000000000) * tbi.denom / tbi.numer;
-#endif
-}
-
-
-inline
-TickVal getTicks() //return !isValid() on error
-{
-#ifdef ZEN_WIN
-    LARGE_INTEGER now = {};
-    if (!::QueryPerformanceCounter(&now))
-        return TickVal();
-    //detailed info about QPC: https://msdn.microsoft.com/en-us/library/windows/desktop/dn553408
-    //- MSDN: "No need to set the thread affinity"
-
-#elif defined ZEN_LINUX
-    //gettimeofday() seems fine but is deprecated
-    timespec now = {};
-    if (::clock_gettime(CLOCK_MONOTONIC_RAW, &now) != 0) //CLOCK_MONOTONIC measures time reliably across processors!
-        return TickVal();
-
-#elif defined ZEN_MAC
-    uint64_t now = ::mach_absolute_time(); //can this call fail???
-#endif
-    return TickVal(now);
-}
-}
-
-#endif //TICK_COUNT_H_3807326223463457