$NetBSD: patch-ad,v 1.1 2005/01/23 17:37:48 taca Exp $

--- lib/tk/menu.rb.orig	2004-12-09 03:13:37.000000000 +0900
+++ lib/tk/menu.rb
@@ -437,14 +437,14 @@ class TkOptionMenubutton<TkMenubutton
     keys = _symbolkey2str(keys)
 
     parent = nil
-    if args[0].kind_of?(TkWindow) || args[0] == nil
+    if !args.empty? && (args[0].kind_of?(TkWindow) || args[0] == nil)
       parent = args.shift 
     else
       parent = keys.delete('parent')
     end
 
     @variable = nil
-    if args[0].kind_of?(TkVariable) || args[0] == nil
+    if !args.empty? && (args[0].kind_of?(TkVariable) || args[0] == nil)
       @variable = args.shift 
     else
       @variable = keys.delete('variable')