diff -up firefox-74.0/widget/gtk/mozcontainer.cpp.mozilla-1609538 firefox-74.0/widget/gtk/mozcontainer.cpp
--- firefox-74.0/widget/gtk/mozcontainer.cpp.mozilla-1609538	2020-03-02 23:04:56.000000000 +0100
+++ firefox-74.0/widget/gtk/mozcontainer.cpp	2020-03-04 12:26:05.561668537 +0100
@@ -164,13 +164,15 @@ void moz_container_move(MozContainer* co
 
   // wl_subsurface_set_position is actually property of parent surface
   // which is effective when parent surface is commited.
-  wl_surface* parent_surface =
-      moz_gtk_widget_get_wl_surface(GTK_WIDGET(container));
-  if (parent_surface) {
-    wl_subsurface_set_position(container->subsurface, container->subsurface_dx,
-                               container->subsurface_dy);
-    wl_surface_commit(parent_surface);
-    container->surface_position_needs_update = false;
+  wl_subsurface_set_position(container->subsurface, container->subsurface_dx,
+                             container->subsurface_dy);
+  container->surface_position_needs_update = false;
+
+  GdkWindow* window = gtk_widget_get_window(GTK_WIDGET(container));
+  if (window) {
+    GdkRectangle rect = (GdkRectangle){.width = gdk_window_get_width(window),
+                                       .height = gdk_window_get_height(window)};
+    gdk_window_invalidate_rect(window, &rect, false);
   }
 }
 
@@ -575,11 +577,15 @@ static void moz_container_set_opaque_reg
   gtk_widget_get_allocation(GTK_WIDGET(container), &allocation);
 
   // Set region to mozcontainer which does not have any offset
-  wl_region* region =
-      CreateOpaqueRegionWayland(0, 0, allocation.width, allocation.height,
-                                container->opaque_region_subtract_corners);
-  wl_surface_set_opaque_region(container->surface, region);
-  wl_region_destroy(region);
+  if (container->opaque_region_subtract_corners) {
+    wl_region* region =
+        CreateOpaqueRegionWayland(0, 0, allocation.width, allocation.height,
+                                  container->opaque_region_subtract_corners);
+    wl_surface_set_opaque_region(container->surface, region);
+    wl_region_destroy(region);
+  } else {
+    wl_surface_set_opaque_region(container->surface, nullptr);
+  }
 }
 
 struct wl_surface* moz_container_get_wl_surface(MozContainer* container) {
diff -up firefox-74.0/widget/gtk/nsWindow.cpp.mozilla-1609538 firefox-74.0/widget/gtk/nsWindow.cpp
--- firefox-74.0/widget/gtk/nsWindow.cpp.mozilla-1609538	2020-03-04 12:23:34.365414768 +0100
+++ firefox-74.0/widget/gtk/nsWindow.cpp	2020-03-04 12:23:34.368414793 +0100
@@ -4866,10 +4866,14 @@ void nsWindow::UpdateTopLevelOpaqueRegio
     return;
   }
 
-  wl_region* region =
-      CreateOpaqueRegionWayland(x, y, width, height, aSubtractCorners);
-  wl_surface_set_opaque_region(surface, region);
-  wl_region_destroy(region);
+  if (!aSubtractCorners) {
+    wl_region* region =
+        CreateOpaqueRegionWayland(x, y, width, height, aSubtractCorners);
+    wl_surface_set_opaque_region(surface, region);
+    wl_region_destroy(region);
+  } else {
+    wl_surface_set_opaque_region(surface, nullptr);
+  }
 
   GdkWindow* window = gtk_widget_get_window(mShell);
   if (window) {