backport mouse capture fixes 00cc023 and dc555a9

00cc023 "fix releasing mouse capture before showing modal dialog"
dc555a9 "notify all windows in capture stack about capture lost, and empty the stack"
closes #16647

src/gtk/dialog.cpp

@@ -136,9 +136,7 @@ int wxDialog::ShowModal()
     // release the mouse if it's currently captured as the window having it
     // will be disabled when this dialog is shown -- but will still keep the
     // capture making it impossible to do anything in the modal dialog itself
-    wxWindow * const win = wxWindow::GetCapture();
-    if ( win )
-        win->GTKReleaseMouseAndNotify();
+    GTKReleaseMouseAndNotify();
 
     wxWindow * const parent = GetParentForModalDialog();
     if ( parent )

src/gtk/msgdlg.cpp

@@ -277,12 +277,6 @@ int wxMessageDialog::ShowModal()
 {
     WX_HOOK_MODAL_DIALOG();
 
-    // break the mouse capture as it would interfere with modal dialog (see
-    // wxDialog::ShowModal)
-    wxWindow * const win = wxWindow::GetCapture();
-    if ( win )
-        win->GTKReleaseMouseAndNotify();
-
     if ( !m_widget )
     {
         GTKCreateMsgDialog();
@@ -290,6 +284,10 @@ int wxMessageDialog::ShowModal()
                      wxT("failed to create GtkMessageDialog") );
     }
 
+    // break the mouse capture as it would interfere with modal dialog (see
+    // wxDialog::ShowModal)
+    GTKReleaseMouseAndNotify();
+
     // This should be necessary, but otherwise the
     // parent TLW will disappear..
     if (m_parent)

src/gtk/utilsgtk.cpp

@@ -299,6 +299,15 @@ bool wxGUIAppTraits::ShowAssertDialog(const wxString& msg)
         GtkWidget *dialog = gtk_assert_dialog_new();
         gtk_assert_dialog_set_message(GTK_ASSERT_DIALOG(dialog), msg.mb_str());
 
+        GdkDisplay* display = gtk_widget_get_display(dialog);
+#ifdef __WXGTK3__
+        GdkDeviceManager* manager = gdk_display_get_device_manager(display);
+        GdkDevice* device = gdk_device_manager_get_client_pointer(manager);
+        gdk_device_ungrab(device, unsigned(GDK_CURRENT_TIME));
+#else
+        gdk_display_pointer_ungrab(display, unsigned(GDK_CURRENT_TIME));
+#endif
+
 #if wxUSE_STACKWALKER
         // save the current stack ow...
         StackDump dump(GTK_ASSERT_DIALOG(dialog));

src/gtk/window.cpp

@@ -2030,9 +2030,7 @@ gtk_window_grab_broken( GtkWidget*,
     // Mouse capture has been lost involuntarily, notify the application
     if(!event->keyboard && wxWindow::GetCapture() == win)
     {
-        wxMouseCaptureLostEvent evt( win->GetId() );
-        evt.SetEventObject( win );
-        win->HandleWindowEvent( evt );
+        wxWindowGTK::GTKHandleCaptureLost();
     }
     return false;
 }
@@ -4799,10 +4797,22 @@ void wxWindowGTK::DoReleaseMouse()
 
 void wxWindowGTK::GTKReleaseMouseAndNotify()
 {
-    DoReleaseMouse();
-    wxMouseCaptureLostEvent evt(GetId());
-    evt.SetEventObject( this );
-    HandleWindowEvent( evt );
+    GdkDisplay* display = gtk_widget_get_display(m_widget);
+#ifdef __WXGTK3__
+    GdkDeviceManager* manager = gdk_display_get_device_manager(display);
+    GdkDevice* device = gdk_device_manager_get_client_pointer(manager);
+    gdk_device_ungrab(device, unsigned(GDK_CURRENT_TIME));
+#else
+    gdk_display_pointer_ungrab(display, unsigned(GDK_CURRENT_TIME));
+#endif
+    g_captureWindow = NULL;
+    NotifyCaptureLost();
+}
+
+void wxWindowGTK::GTKHandleCaptureLost()
+{
+    g_captureWindow = NULL;
+    NotifyCaptureLost();
 }
 
 /* static */