From d0dd08f88d98127863f07ae9e7fd9ff959322521 Mon Sep 17 00:00:00 2001
From: Piro / SHIMODA Hiroshi <piro@p.club.ne.jp>
Date: Sat, 10 Dec 2011 02:37:41 +0900
Subject: [PATCH] don't raise "undefined" error

---
 content/treestyletab/group.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/content/treestyletab/group.js b/content/treestyletab/group.js
index 32933aa8..792b6f84 100644
--- a/content/treestyletab/group.js
+++ b/content/treestyletab/group.js
@@ -134,7 +134,9 @@ function getOwnerTabBrowser()
 function getOwnerTab(aWindow)
 {
 	var gBrowser = getOwnerTabBrowser();
-	return gBrowser && gBrowser.treeStyleTab.getTabFromFrame(aWindow || window);
+	return gBrowser &&
+			gBrowser.treeStyleTab &&
+			gBrowser.treeStyleTab.getTabFromFrame(aWindow || window);
 }
 
 function getTabById(aId)