diff --git a/gdk/x11/gdkdisplay-x11.c b/gdk/x11/gdkdisplay-x11.c
index cf0752a27d..6ee667545f 100644
--- a/gdk/x11/gdkdisplay-x11.c
+++ b/gdk/x11/gdkdisplay-x11.c
@@ -2722,6 +2722,8 @@ gdk_x11_display_class_init (GdkX11DisplayClass * class)
   object_class->dispose = gdk_x11_display_dispose;
   object_class->finalize = gdk_x11_display_finalize;
 
+  display_class->window_type = GDK_TYPE_X11_WINDOW;
+
   display_class->get_name = gdk_x11_display_get_name;
   display_class->get_n_screens = gdk_x11_display_get_n_screens;
   display_class->get_screen = gdk_x11_display_get_screen;
diff --git a/gdk/x11/gdkwindow-x11.c b/gdk/x11/gdkwindow-x11.c
index de7c6916a1..5cc9fd20e4 100644
--- a/gdk/x11/gdkwindow-x11.c
+++ b/gdk/x11/gdkwindow-x11.c
@@ -128,6 +128,27 @@ static void        gdk_window_impl_x11_finalize   (GObject            *object);
     (( time1 < time2 ) && ( time2 - time1 > ((guint32)-1)/2 ))     \
   )
 
+struct _GdkX11Window {
+  GdkWindow parent;
+};
+
+struct _GdkX11WindowClass {
+  GdkWindowClass parent_class;
+};
+
+G_DEFINE_TYPE (GdkX11Window, gdk_x11_window, GDK_TYPE_WINDOW)
+
+static void
+gdk_x11_window_class_init (GdkX11WindowClass *x11_window_class)
+{
+}
+
+static void
+gdk_x11_window_init (GdkX11Window *x11_window)
+{
+}
+
+
 G_DEFINE_TYPE (GdkWindowImplX11, gdk_window_impl_x11, GDK_TYPE_WINDOW_IMPL)
 
 static void
diff --git a/gdk/x11/gdkx11window.h b/gdk/x11/gdkx11window.h
index f1c8971c45..ecfbea5c8d 100644
--- a/gdk/x11/gdkx11window.h
+++ b/gdk/x11/gdkx11window.h
@@ -38,6 +38,22 @@
 
 G_BEGIN_DECLS
 
+#define GDK_TYPE_X11_WINDOW              (gdk_x11_window_get_type ())
+#define GDK_X11_WINDOW(object)           (G_TYPE_CHECK_INSTANCE_CAST ((object), GDK_TYPE_X11_WINDOW, GdkX11Window))
+#define GDK_X11_WINDOW_CLASS(klass)      (G_TYPE_CHECK_CLASS_CAST ((klass), GDK_TYPE_X11_WINDOW, GdkX11WindowClass))
+#define GDK_IS_X11_WINDOW(object)        (G_TYPE_CHECK_INSTANCE_TYPE ((object), GDK_TYPE_X11_WINDOW))
+#define GDK_IS_X11_WINDOW_CLASS(klass)   (G_TYPE_CHECK_CLASS_TYPE ((klass), GDK_TYPE_X11_WINDOW))
+#define GDK_X11_WINDOW_GET_CLASS(obj)    (G_TYPE_INSTANCE_GET_CLASS ((obj), GDK_TYPE_X11_WINDOW, GdkX11WindowClass))
+
+#ifdef GDK_COMPILATION
+typedef struct _GdkX11Window GdkX11Window;
+#else
+typedef GdkWindow GdkX11Window;
+#endif
+typedef struct _GdkX11WindowClass GdkX11WindowClass;
+
+GType    gdk_x11_window_get_type          (void);
+
 Window   gdk_x11_window_get_xid           (GdkWindow   *window);
 void     gdk_x11_window_set_user_time     (GdkWindow   *window,
                                            guint32      timestamp);