diff --git a/content/treestyletab/hacks.js b/content/treestyletab/hacks.js
index 4cc3a0a6..542fe24c 100644
--- a/content/treestyletab/hacks.js
+++ b/content/treestyletab/hacks.js
@@ -210,9 +210,7 @@ TreeStyleTabService.overrideExtensionsPreInit = function TSTService_overrideExte
 	// TooManyTabs
 	// https://addons.mozilla.org/firefox/addon/9429
 	if ('tooManyTabs' in window) {
-		this.registerExpandTwistyAreaAllowance(function(aTabBrowser) {
-			return false;
-		});
+		this.registerExpandTwistyAreaBlocker('tooManyTabs');
 	}
 };
 
diff --git a/content/treestyletab/treestyletab.js b/content/treestyletab/treestyletab.js
index 74cfb75a..3191b987 100644
--- a/content/treestyletab/treestyletab.js
+++ b/content/treestyletab/treestyletab.js
@@ -1,15 +1,4 @@
 var TreeStyleTabService = { 
-
-	get treeBundle() {
-		return window['piro.sakura.ne.jp']
-				.stringBundle
-				.get('chrome://treestyletab/locale/treestyletab.properties');
-	},
-	get tabbrowserBundle() {
-		return window['piro.sakura.ne.jp']
-				.stringBundle
-				.get('chrome://browser/locale/tabbrowser.properties');
-	},
 	
 /* API */ 
 	
@@ -85,32 +74,6 @@ var TreeStyleTabService = {
 		window['piro.sakura.ne.jp'].stopRendering.start();
 	},
  
-	isEventFiredOnTwisty : function TSTService_isEventFiredOnTwisty(aEvent) 
-	{
-		var tab = this.getTabFromEvent(aEvent);
-		if (!tab || !this.hasChildTabs(tab)) return false;
-
-		var expression = 'ancestor-or-self::*[@class="'+this.kTWISTY+'"]';
-		if (this.canExpandTwistyArea(this.getTabBrowserFromChild(tab)))
-			expression += ' | ancestor-or-self::*[@class="tab-icon" and ancestor::xul:tabbrowser[@'+this.kMODE+'="vertical"]]';
-
-		return this.evaluateXPath(
-				expression,
-				aEvent.originalTarget || aEvent.target,
-				XPathResult.BOOLEAN_TYPE
-			).booleanValue;
-	},
-	
-	canExpandTwistyArea : function TSTService_canExpandTwistyArea(aTabBrowser) 
-	{
-		return (
-				this.expandTwistyArea &&
-				this._expandTwistyAreaAllowance.every(function(aFunc) {
-					return aFunc.call(this, aTabBrowser);
-				}, this)
-			);
-	},
-  
 	getPropertyPixelValue : function TSTService_getPropertyPixelValue(aElementOrStyle, aProp) 
 	{
 		var style = aElementOrStyle instanceof Components.interfaces.nsIDOMCSSStyleDeclaration ?
@@ -118,79 +81,6 @@ var TreeStyleTabService = {
 					window.getComputedStyle(aElementOrStyle, null) ;
 		return Number(style.getPropertyValue(aProp).replace(/px$/, ''));
 	},
- 
-	dropLinksOnTabBehavior : function TSTService_dropLinksOnTabBehavior() 
-	{
-		var behavior = this.getTreePref('dropLinksOnTab.behavior');
-		if (behavior & this.kDROPLINK_FIXED) return behavior;
-
-		var checked = { value : false };
-		var newChildTab = this.PromptService.confirmEx(window,
-				this.treeBundle.getString('dropLinkOnTab.title'),
-				this.treeBundle.getString('dropLinkOnTab.text'),
-				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_0) +
-				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_1),
-				this.treeBundle.getString('dropLinkOnTab.openNewChildTab'),
-				this.treeBundle.getString('dropLinkOnTab.loadInTheTab'),
-				null,
-				this.treeBundle.getString('dropLinkOnTab.never'),
-				checked
-			) == 0;
-
-		behavior = newChildTab ? this.kDROPLINK_NEWTAB : this.kDROPLINK_LOAD ;
-		if (checked.value)
-			this.setTreePref('dropLinksOnTab.behavior', behavior);
-
-		return behavior
-	},
-	kDROPLINK_ASK    : 0,
-	kDROPLINK_FIXED  : 1 + 2,
-	kDROPLINK_LOAD   : 1,
-	kDROPLINK_NEWTAB : 2,
- 
-	openGroupBookmarkBehavior : function TSTService_openGroupBookmarkBehavior() 
-	{
-		var behavior = this.getTreePref('openGroupBookmark.behavior');
-		if (behavior & this.kGROUP_BOOKMARK_FIXED) return behavior;
-
-		var dummyTabFlag = behavior & this.kGROUP_BOOKMARK_USE_DUMMY;
-
-		var checked = { value : false };
-		var button = this.PromptService.confirmEx(window,
-				this.treeBundle.getString('openGroupBookmarkBehavior.title'),
-				this.treeBundle.getString('openGroupBookmarkBehavior.text'),
-				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_0) +
-				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_1) +
-				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_2),
-				this.treeBundle.getString('openGroupBookmarkBehavior.subTree'),
-				this.treeBundle.getString('openGroupBookmarkBehavior.separate'),
-				this.treeBundle.getString('openGroupBookmarkBehavior.replace'),
-				this.treeBundle.getString('openGroupBookmarkBehavior.never'),
-				checked
-			);
-
-		if (button < 0) button = 1;
-		var behaviors = [
-				this.kGROUP_BOOKMARK_SUBTREE | dummyTabFlag,
-				this.kGROUP_BOOKMARK_SEPARATE,
-				this.kGROUP_BOOKMARK_REPLACE
-			];
-		behavior = behaviors[button];
-
-		if (checked.value) {
-			this.setTreePref('openGroupBookmark.behavior', behavior);
-			this.setPref('browser.tabs.loadFolderAndReplace', behavior & this.kGROUP_BOOKMARK_REPLACE ? true : false );
-		}
-		return behavior;
-	},
-	kGROUP_BOOKMARK_ASK       : 0,
-	kGROUP_BOOKMARK_FIXED     : 1 + 2 + 4,
-	kGROUP_BOOKMARK_SUBTREE   : 1,
-	kGROUP_BOOKMARK_SEPARATE  : 2,
-	kGROUP_BOOKMARK_REPLACE   : 4,
-	kGROUP_BOOKMARK_USE_DUMMY : 256,
-	kGROUP_BOOKMARK_USE_DUMMY_FORCE : 1024,
-	kGROUP_BOOKMARK_DONT_RESTORE_TREE_STRUCTURE : 512,
   
 /* Initializing */ 
 	
@@ -1570,12 +1460,6 @@ catch(e) {
 	},
 	_tabFocusAllowance : [],
  
-	registerExpandTwistyAreaAllowance : function TSTService_registerExpandTwistyAreaAllowance(aProcess) /* PUBLIC API */ 
-	{
-		this._expandTwistyAreaAllowance.push(aProcess);
-	},
-	_expandTwistyAreaAllowance : [],
- 
 	tearOffSubtreeFromRemote : function TSTService_tearOffSubtreeFromRemote() 
 	{
 		var remoteTab = window.arguments[0];
diff --git a/content/treestyletab/res/stringBundle.js b/modules/stringBundle.js
similarity index 93%
rename from content/treestyletab/res/stringBundle.js
rename to modules/stringBundle.js
index b636e5b8..caf72df0 100644
--- a/content/treestyletab/res/stringBundle.js
+++ b/modules/stringBundle.js
@@ -1,3 +1,6 @@
+var EXPORTED_SYMBOLS = ['window'];
+var window = {};
+
 /*
  string bundle utility
 
diff --git a/modules/utils.js b/modules/utils.js
index 22726b53..d60c23ec 100644
--- a/modules/utils.js
+++ b/modules/utils.js
@@ -40,9 +40,15 @@ var Ci = Components.interfaces;
  
 var prefs = {}; 
 Components.utils.import('resource://treestyletab-modules/prefs.js', prefs);
+prefs = prefs.window['piro.sakura.ne.jp'].prefs;
 
-var boxObject = {}; 
+var boxObject = {};
 Components.utils.import('resource://treestyletab-modules/boxObject.js', boxObject);
+boxObject = boxObject.window['piro.sakura.ne.jp'].boxObject;
+
+var stringBundle = {};
+Components.utils.import('resource://treestyletab-modules/stringBundle.js', stringBundle);
+stringBundle = stringBundle.window['piro.sakura.ne.jp'].stringBundle;
  
 var TreeStyleTabUtils = { 
 	
@@ -143,7 +149,7 @@ var TreeStyleTabUtils = {
 	indentDuration   : 200,
 	collapseDuration : 150,
 
-	expandTwistyArea : true,
+	shouldExpandTwistyArea : true,
  
 	get SessionStore() { 
 		if (!this._SessionStore) {
@@ -212,6 +218,15 @@ var TreeStyleTabUtils = {
 	},
 	_Comparator : null,
  
+	get treeBundle() { 
+		return stringBundle
+				.get('chrome://treestyletab/locale/treestyletab.properties');
+	},
+	get tabbrowserBundle() {
+		return stringBundle
+				.get('chrome://browser/locale/tabbrowser.properties');
+	},
+ 
 	init : function TSTUtils_init() 
 	{
 		if (this._initialized) return;
@@ -261,7 +276,7 @@ var TreeStyleTabUtils = {
 	
 	getBoxObjectFor : function TSTUtils_getBoxObjectFor(aNode) 
 	{
-		return boxObject.window['piro.sakura.ne.jp'].boxObject.getBoxObjectFor(aNode);
+		return boxObject.getBoxObjectFor(aNode);
 	},
  
 	get browserWindow() 
@@ -277,6 +292,79 @@ var TreeStyleTabUtils = {
 			w.gBrowser ;
 	},
  
+	dropLinksOnTabBehavior : function TSTUtils_dropLinksOnTabBehavior() 
+	{
+		var behavior = this.getTreePref('dropLinksOnTab.behavior');
+		if (behavior & this.kDROPLINK_FIXED) return behavior;
+
+		var checked = { value : false };
+		var newChildTab = this.PromptService.confirmEx(this.browserWindow,
+				this.treeBundle.getString('dropLinkOnTab.title'),
+				this.treeBundle.getString('dropLinkOnTab.text'),
+				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_0) +
+				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_1),
+				this.treeBundle.getString('dropLinkOnTab.openNewChildTab'),
+				this.treeBundle.getString('dropLinkOnTab.loadInTheTab'),
+				null,
+				this.treeBundle.getString('dropLinkOnTab.never'),
+				checked
+			) == 0;
+
+		behavior = newChildTab ? this.kDROPLINK_NEWTAB : this.kDROPLINK_LOAD ;
+		if (checked.value)
+			this.setTreePref('dropLinksOnTab.behavior', behavior);
+
+		return behavior
+	},
+	kDROPLINK_ASK    : 0,
+	kDROPLINK_FIXED  : 1 + 2,
+	kDROPLINK_LOAD   : 1,
+	kDROPLINK_NEWTAB : 2,
+ 
+	openGroupBookmarkBehavior : function TSTUtils_openGroupBookmarkBehavior() 
+	{
+		var behavior = this.getTreePref('openGroupBookmark.behavior');
+		if (behavior & this.kGROUP_BOOKMARK_FIXED) return behavior;
+
+		var dummyTabFlag = behavior & this.kGROUP_BOOKMARK_USE_DUMMY;
+
+		var checked = { value : false };
+		var button = this.PromptService.confirmEx(this.browserWindow,
+				this.treeBundle.getString('openGroupBookmarkBehavior.title'),
+				this.treeBundle.getString('openGroupBookmarkBehavior.text'),
+				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_0) +
+				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_1) +
+				(this.PromptService.BUTTON_TITLE_IS_STRING * this.PromptService.BUTTON_POS_2),
+				this.treeBundle.getString('openGroupBookmarkBehavior.subTree'),
+				this.treeBundle.getString('openGroupBookmarkBehavior.separate'),
+				this.treeBundle.getString('openGroupBookmarkBehavior.replace'),
+				this.treeBundle.getString('openGroupBookmarkBehavior.never'),
+				checked
+			);
+
+		if (button < 0) button = 1;
+		var behaviors = [
+				this.kGROUP_BOOKMARK_SUBTREE | dummyTabFlag,
+				this.kGROUP_BOOKMARK_SEPARATE,
+				this.kGROUP_BOOKMARK_REPLACE
+			];
+		behavior = behaviors[button];
+
+		if (checked.value) {
+			this.setTreePref('openGroupBookmark.behavior', behavior);
+			this.setPref('browser.tabs.loadFolderAndReplace', behavior & this.kGROUP_BOOKMARK_REPLACE ? true : false );
+		}
+		return behavior;
+	},
+	kGROUP_BOOKMARK_ASK       : 0,
+	kGROUP_BOOKMARK_FIXED     : 1 + 2 + 4,
+	kGROUP_BOOKMARK_SUBTREE   : 1,
+	kGROUP_BOOKMARK_SEPARATE  : 2,
+	kGROUP_BOOKMARK_REPLACE   : 4,
+	kGROUP_BOOKMARK_USE_DUMMY : 256,
+	kGROUP_BOOKMARK_USE_DUMMY_FORCE : 1024,
+	kGROUP_BOOKMARK_DONT_RESTORE_TREE_STRUCTURE : 512,
+ 
 // event 
 	
 	isNewTabAction : function TSTUtils_isNewTabAction(aEvent) 
@@ -314,7 +402,35 @@ var TreeStyleTabUtils = {
 				Ci.nsIDOMXPathResult.BOOLEAN_TYPE
 			).booleanValue;
 	},
-  
+ 
+	isEventFiredOnTwisty : function TSTUtils_isEventFiredOnTwisty(aEvent) 
+	{
+		var tab = this.getTabFromEvent(aEvent);
+		if (!tab || !this.hasChildTabs(tab)) return false;
+
+		var expression = 'ancestor-or-self::*[@class="'+this.kTWISTY+'"]';
+		if (this.shouldExpandTwistyArea && !this._expandTwistyAreaBlockeds.length)
+			expression += ' | ancestor-or-self::*[@class="tab-icon" and ancestor::xul:tabbrowser[@'+this.kMODE+'="vertical"]]';
+
+		return this.evaluateXPath(
+				expression,
+				aEvent.originalTarget || aEvent.target,
+				XPathResult.BOOLEAN_TYPE
+			).booleanValue;
+	},
+	
+	registerExpandTwistyAreaBlocker : function TSTUtils_registerExpandTwistyAreaBlocker(aBlocker) /* PUBLIC API */ 
+	{
+		if (this._expandTwistyAreaBlockeds.indexOf(aBlocker) < 0)
+			this._expandTwistyAreaBlockeds.push(aBlocker);
+	},
+	_expandTwistyAreaBlockeds : [],
+ 
+	registerExpandTwistyAreaAllowance : function TSTUtils_registerExpandTwistyAreaAllowance(aAllowance) /* PUBLIC API, obsolete, for backward compatibility */ 
+	{
+		this.registerExpandTwistyAreaBlocker(aAllowance.toSource());
+	},
+   
 // string 
 	
 	makeNewId : function TSTUtils_makeNewId() 
@@ -1367,7 +1483,7 @@ var TreeStyleTabUtils = {
 				break;
 
 			case 'extensions.treestyletab.twisty.expandSensitiveArea':
-				this.expandTwistyArea = value;
+				this.shouldExpandTwistyArea = value;
 				break;
 
 			default:
@@ -1408,5 +1524,5 @@ var TreeStyleTabUtils = {
   
 }; 
  
-TreeStyleTabUtils.__proto__ = prefs.window['piro.sakura.ne.jp'].prefs; 
+TreeStyleTabUtils.__proto__ = prefs;