Index: gtk/gtktogglebutton.c
===================================================================
--- gtk/gtktogglebutton.c	(revision 22218)
+++ gtk/gtktogglebutton.c	(working copy)
@@ -502,7 +502,8 @@
 
   g_object_notify (G_OBJECT (toggle_button), "active");
 
-  GTK_BUTTON_CLASS (gtk_toggle_button_parent_class)->clicked (button);
+  if (GTK_BUTTON_CLASS (gtk_toggle_button_parent_class)->clicked)
+    GTK_BUTTON_CLASS (gtk_toggle_button_parent_class)->clicked (button);
 }
 
 static void