--- gtk+-2.18.3/gtk/gtkwindow.c	2009-10-09 01:00:44.000000000 -0400
+++ hacked/gtk/gtkwindow.c	2009-10-28 11:45:33.583105288 -0400
@@ -2414,7 +2414,7 @@
   GtkWindowPrivate *priv;
 
   g_return_if_fail (GTK_IS_WINDOW (window));
-  g_return_if_fail (!GTK_WIDGET_VISIBLE (window));
+  g_return_if_fail (!GTK_WIDGET_MAPPED (window));
 
   priv = GTK_WINDOW_GET_PRIVATE (window);