diff --git a/content/treestyletab/treestyletabbrowser.js b/content/treestyletab/treestyletabbrowser.js
index 53748fb4..207f554c 100644
--- a/content/treestyletab/treestyletabbrowser.js
+++ b/content/treestyletab/treestyletabbrowser.js
@@ -546,8 +546,8 @@ TreeStyleTabBrowser.prototype = {
 		this.onPrefChange('extensions.treestyletab.tabbar.invertTabContents');
 		this.onPrefChange('extensions.treestyletab.tabbar.invertClosebox');
 
-		var tabContextMenu = document.getAnonymousElementByAttribute(b, 'anonid', 'tabContextMenu') ||
-							document.getAnonymousElementByAttribute(b.tabContainer, 'anonid', 'tabContextMenu');
+		var tabContextMenu = b.tabContextMenu ||
+							document.getAnonymousElementByAttribute(b, 'anonid', 'tabContextMenu');
 		tabContextMenu.addEventListener('popupshowing', this, false);
 		if (!('MultipleTabService' in window)) {
 			window.setTimeout(function(aSelf, aTabBrowser, aPopup) {
@@ -1293,8 +1293,8 @@ TreeStyleTabBrowser.prototype = {
 		this.scrollBox.removeEventListener('overflow', this, true);
 		this.scrollBox.removeEventListener('underflow', this, true);
 
-		var tabContextMenu = document.getAnonymousElementByAttribute(b, 'anonid', 'tabContextMenu') ||
-							document.getAnonymousElementByAttribute(b.tabContainer, 'anonid', 'tabContextMenu');
+		var tabContextMenu = b.tabContextMenu ||
+							document.getAnonymousElementByAttribute(b, 'anonid', 'tabContextMenu');
 		tabContextMenu.removeEventListener('popupshowing', this, false);
 
 		var allTabPopup = document.getAnonymousElementByAttribute(b.mTabContainer, 'anonid', 'alltabs-popup');
diff --git a/modules/utils.js b/modules/utils.js
index a9a44013..28eaf421 100644
--- a/modules/utils.js
+++ b/modules/utils.js
@@ -662,7 +662,10 @@ var TreeStyleTabUtils = {
 	
 	getTabStrip : function TSTUtils_getTabStrip(aTabBrowser) 
 	{
-		return aTabBrowser.mStrip || aTabBrowser.tabContainer.parentNode;
+		var strip = aTabBrowser.mStrip;
+		return (strip && strip.localName == 'hbox') ?
+				strip :
+				aTabBrowser.tabContainer.parentNode;
 	},
 	get tabStrip() 
 	{