forms_set_event_call_back: argument of None resets event callback to NULL.
diff --git a/Modules/flmodule.c b/Modules/flmodule.c
index 90b8115..502ea6c 100644
--- a/Modules/flmodule.c
+++ b/Modules/flmodule.c
@@ -1995,6 +1995,8 @@
 	object *dummy;
 	object *args;
 {
+	if (args == None)
+		args = NULL;
 	my_event_callback = args;
 	XINCREF(args);
 	INCREF(None);