diff --git a/widget/gtk/mozgtk/mozgtk.c b/widget/gtk/mozgtk/mozgtk.c
--- a/widget/gtk/mozgtk/mozgtk.c
+++ b/widget/gtk/mozgtk/mozgtk.c
@@ -224,16 +224,17 @@ STUB(gtk_file_chooser_set_preview_widget
 STUB(gtk_file_chooser_set_preview_widget_active)
 STUB(gtk_file_chooser_set_select_multiple)
 STUB(gtk_file_chooser_widget_get_type)
 STUB(gtk_file_filter_add_pattern)
 STUB(gtk_file_filter_new)
 STUB(gtk_file_filter_set_name)
 STUB(gtk_fixed_new)
 STUB(gtk_frame_new)
+STUB(gtk_get_current_event_time)
 STUB(gtk_grab_add)
 STUB(gtk_grab_remove)
 STUB(gtk_handle_box_new)
 STUB(gtk_hbox_new)
 STUB(gtk_icon_info_free)
 STUB(gtk_icon_info_load_icon)
 STUB(gtk_icon_set_add_source)
 STUB(gtk_icon_set_new)
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -1358,23 +1358,27 @@ SetUserTimeAndStartupIDForActivatedWindo
     // we don't want to reuse the timestamp next time we raise the window
     GTKToolkit->SetFocusTimestamp(0);
     GTKToolkit->SetDesktopStartupID(EmptyCString());
 }
 
 /* static */ guint32
 nsWindow::GetLastUserInputTime()
 {
-    // gdk_x11_display_get_user_time tracks button and key presses,
-    // DESKTOP_STARTUP_ID used to start the app, drop events from external
-    // drags, WM_DELETE_WINDOW delete events, but not usually mouse motion nor
+    // gdk_x11_display_get_user_time/gtk_get_current_event_time tracks
+    // button and key presses, DESKTOP_STARTUP_ID used to start the app,
+    // drop events from external drags,
+    // WM_DELETE_WINDOW delete events, but not usually mouse motion nor
     // button and key releases.  Therefore use the most recent of
     // gdk_x11_display_get_user_time and the last time that we have seen.
-    guint32 timestamp =
-            gdk_x11_display_get_user_time(gdk_display_get_default());
+    GdkDisplay* gdkDisplay = gdk_display_get_default();
+    guint32 timestamp = GDK_IS_X11_DISPLAY(gdkDisplay) ?
+            gdk_x11_display_get_user_time(gdkDisplay) :
+            gtk_get_current_event_time();
+
     if (sLastUserInputTime != GDK_CURRENT_TIME &&
         TimestampIsNewerThan(sLastUserInputTime, timestamp)) {
         return sLastUserInputTime;
     }
 
     return timestamp;
 }