(gecko:11471): Gtk-WARNING **: Can't set a parent on widget which has a parent
(gecko:11471): Gtk-CRITICAL **: gtk_widget_destroy: assertion `GTK_IS_WIDGET (widget)' failed
(gecko:11471): Gtk-CRITICAL **: gtk_widget_destroy: assertion `GTK_IS_WIDGET (widget)' failed
(gecko:20570): GLib-GObject-WARNING **: invalid uninstantiatable type `(null)' in cast to `GtkWidget'
(gecko:20570): GLib-GObject-WARNING **: invalid uninstantiatable type `(null)' in cast to `GObject'
(gecko:20570): GLib-GObject-CRITICAL **: g_object_get_data: assertion `G_IS_OBJECT (object)' failed