gesture-grabber: Ignore events not meant for the root window

The passive touch grab is set on the root window, so if touch
events get to a different window it's best to leave those for
GTK+ to handle.

Signed-off-by: Carlos Garnacho <carlos@lanedo.com>
Acked-by: Simon Schampijer <simon@laptop.org>

src/sugar3/sugar-gesture-grabber.c

@@ -256,6 +256,7 @@ filter_function (GdkXEvent *xevent,
         SugarGestureGrabber *grabber;
         SugarGestureGrabberPriv *priv;
         gboolean handled = FALSE;
+        Window event_window;
         GdkDevice *device;
         XIDeviceEvent *ev;
         GdkDisplay *display;
@@ -285,6 +286,9 @@ filter_function (GdkXEvent *xevent,
                 return GDK_FILTER_CONTINUE;
         }
 
+        if (ev->event != gdk_x11_window_get_xid (priv->root_window))
+                return GDK_FILTER_CONTINUE;
+
         event->touch.window = g_object_ref (priv->root_window);
         event->touch.time = ev->time;
         event->touch.x = ev->event_x;