x11: Only use state of toplevels

Other surface subtypes don't have that property.

diff --git a/gdk/x11/gdkmonitor-x11.c b/gdk/x11/gdkmonitor-x11.c
index 341917ad8cc4773f8e1099025f54ddb1cfb57c32..85e192405374017fe2b6a9c05910ba2636422ed2 100644 (file)
--- a/gdk/x11/gdkmonitor-x11.c
+++ b/gdk/x11/gdkmonitor-x11.c
@@ -44,6 +44,9 @@ gdk_monitor_has_fullscreen_window (GdkMonitor *monitor)
     {
       surface = l->data;
 
+      if (!GDK_IS_TOPLEVEL (surface))
+        continue;
+
       if ((gdk_toplevel_get_state (GDK_TOPLEVEL (surface)) & GDK_SURFACE_STATE_FULLSCREEN) == 0)
         continue;