[GTK3] Unregister tick callback and properly close the window. Fixes #1424

src/Gtk/Avalonia.Gtk3/Interop/Native.cs

@@ -219,7 +219,10 @@ namespace Avalonia.Gtk3.Interop
             public delegate void gtk_widget_queue_draw_area(GtkWidget widget, int x, int y, int width, int height);
             
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
-            public delegate void gtk_widget_add_tick_callback(GtkWidget widget, TickCallback callback, IntPtr userData, IntPtr destroy);
+            public delegate uint gtk_widget_add_tick_callback(GtkWidget widget, TickCallback callback, IntPtr userData, IntPtr destroy);
+            
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
+            public delegate uint gtk_widget_remove_tick_callback(GtkWidget widget, uint id);
 
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate GtkImContext gtk_im_multicontext_new();
@@ -256,6 +259,9 @@ namespace Avalonia.Gtk3.Interop
 
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_window_unmaximize(GtkWindow window);
+            
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
+            public delegate void gtk_window_close(GtkWindow window);
 
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gdk)]
             public delegate void gtk_window_set_geometry_hints(GtkWindow window, IntPtr geometry_widget, ref GdkGeometry geometry, GdkWindowHints geom_mask);
@@ -434,6 +440,7 @@ namespace Avalonia.Gtk3.Interop
         public static D.gdk_window_invalidate_rect GdkWindowInvalidateRect;
         public static D.gtk_widget_queue_draw_area GtkWidgetQueueDrawArea;
         public static D.gtk_widget_add_tick_callback GtkWidgetAddTickCallback;
+        public static D.gtk_widget_remove_tick_callback GtkWidgetRemoveTickCallback;
         public static D.gtk_widget_activate GtkWidgetActivate;
         public static D.gtk_clipboard_get_for_display GtkClipboardGetForDisplay;
         public static D.gtk_clipboard_request_text GtkClipboardRequestText;
@@ -456,6 +463,7 @@ namespace Avalonia.Gtk3.Interop
         public static D.gtk_window_deiconify GtkWindowDeiconify;
         public static D.gtk_window_maximize GtkWindowMaximize;
         public static D.gtk_window_unmaximize GtkWindowUnmaximize;
+        public static D.gtk_window_close GtkWindowClose;
         public static D.gdk_window_begin_move_drag GdkWindowBeginMoveDrag;
         public static D.gdk_window_begin_resize_drag GdkWindowBeginResizeDrag;
         public static D.gdk_event_request_motions GdkEventRequestMotions;

src/Gtk/Avalonia.Gtk3/WindowBaseImpl.cs

@@ -33,11 +33,11 @@ namespace Avalonia.Gtk3
         private readonly AutoResetEvent _canSetNextOperation = new AutoResetEvent(true);
         internal IntPtr? GdkWindowHandle;
         private bool _overrideRedirect;
+        private uint? _tickCallback;
         public WindowBaseImpl(GtkWindow gtkWidget)
         {
             
             GtkWidget = gtkWidget;
-            Disposables.Add(gtkWidget);
             _framebuffer = new FramebufferManager(this);
             _imContext = Native.GtkImMulticontextNew();
             Disposables.Add(_imContext);
@@ -62,7 +62,7 @@ namespace Avalonia.Gtk3
             {
                 Native.GtkWidgetSetDoubleBuffered(gtkWidget, false);
                 _gcHandle = GCHandle.Alloc(this);
-                Native.GtkWidgetAddTickCallback(GtkWidget, PinnedStaticCallback, GCHandle.ToIntPtr(_gcHandle), IntPtr.Zero);
+                _tickCallback = Native.GtkWidgetAddTickCallback(GtkWidget, PinnedStaticCallback, GCHandle.ToIntPtr(_gcHandle), IntPtr.Zero);
                 
             }
         }
@@ -103,7 +103,7 @@ namespace Avalonia.Gtk3
 
         private bool OnDestroy(IntPtr gtkwidget, IntPtr userdata)
         {
-            Dispose();
+            DoDispose(true);
             return false;
         }
 
@@ -297,14 +297,28 @@ namespace Avalonia.Gtk3
         }
 
 
-        public void Dispose()
+        public void Dispose() => DoDispose(false);
+        
+        void DoDispose(bool fromDestroy)
         {
+            if (_tickCallback.HasValue)
+            {
+                if (!GtkWidget.IsClosed)
+                    Native.GtkWidgetRemoveTickCallback(GtkWidget, _tickCallback.Value);
+                _tickCallback = null;
+            }
+            
             //We are calling it here, since signal handler will be detached
             if (!GtkWidget.IsClosed)
                 Closed?.Invoke();
             foreach(var d in Disposables.AsEnumerable().Reverse())
                 d.Dispose();
             Disposables.Clear();
+            
+            if (!fromDestroy && !GtkWidget.IsClosed)
+                Native.GtkWindowClose(GtkWidget);
+            GtkWidget.Dispose();
+            
             if (_gcHandle.IsAllocated)
             {
                 _gcHandle.Free();