diff --git a/content/treestyletab/config.js b/content/treestyletab/config.js
index aee36b62..e0fa3faa 100644
--- a/content/treestyletab/config.js
+++ b/content/treestyletab/config.js
@@ -3,6 +3,23 @@ const XULAppInfo = Components.classes['@mozilla.org/xre/app-info;1']
 const comparator = Components.classes['@mozilla.org/xpcom/version-comparator;1']
 					.getService(Components.interfaces.nsIVersionComparator);
 
+function init()
+{
+	var useEffectiveTLD = document.getElementById('useEffectiveTLD');
+	var fx2Items = document.getElementsByAttribute('label-fx2', '*');
+	if (comparator.compare(XULAppInfo.version, '3.0') < 0) {
+		useEffectiveTLD.setAttribute('collapsed', true);
+		Array.slice(fx2Items).forEach(function(aItem) {
+			aItem.setAttribute('label', aItem.getAttribute('label-fx2'));
+		});
+	}
+	else {
+		useEffectiveTLD.removeAttribute('collapsed');
+	}
+
+	sizeToContent();
+}
+
 
 var gOuterLinkCheck,
 	gAnyLinkCheck,
@@ -50,13 +67,6 @@ function initTabPane()
 
 	gLastStateIsVertical = document.getElementById('extensions.treestyletab.tabbar.position-radiogroup').value;
 	gLastStateIsVertical = gLastStateIsVertical == 'left' || gLastStateIsVertical == 'right';
-
-	var fx2Items = document.getElementsByAttribute('label-fx2', '*');
-	if (comparator.compare(XULAppInfo.version, '3.0') < 0) {
-		Array.slice(fx2Items).forEach(function(aItem) {
-			aItem.setAttribute('label', aItem.getAttribute('label-fx2'));
-		});
-	}
 }
 
 function onChangeGroupBookmarkRadio()
diff --git a/content/treestyletab/config.xul b/content/treestyletab/config.xul
index bb229ea3..853958b0 100644
--- a/content/treestyletab/config.xul
+++ b/content/treestyletab/config.xul
@@ -9,7 +9,7 @@
 <prefwindow id="treestyletab-config"
 	xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
 	title="&config.title;"
-	onload="sizeToContent();">
+	onload="init()">
 
 <prefpane id="prefpane-appearance" label="&config.tabs.appearance;"
 	onpaneload="onChangeTabbarPosition();">
@@ -511,6 +511,9 @@
 		<preference id="extensions.treestyletab.insertNewChildAt"
 			name="extensions.treestyletab.insertNewChildAt"
 			type="int"/>
+		<preference id="extensions.treestyletab.useEffectiveTLD"
+			name="extensions.treestyletab.useEffectiveTLD"
+			type="bool"/>
 	</preferences>
 
 	<vbox>
@@ -548,6 +551,15 @@
 			<radio value="1" label="&config.insertNewChildAt.last;"/>
 		</radiogroup>
 	</groupbox>
+	<groupbox id="useEffectiveTLD">
+		<caption label="&config.useEffectiveTLD.caption;"/>
+		<radiogroup id="extensions.treestyletab.useEffectiveTLD-radiogroup"
+			preference="extensions.treestyletab.useEffectiveTLD"
+			orient="vertical">
+			<radio value="true" label="&config.useEffectiveTLD.enabled;"/>
+			<radio value="false" label="&config.useEffectiveTLD.disabled;"/>
+		</radiogroup>
+	</groupbox>
 
 	</vbox>
 </prefpane>
diff --git a/locale/de-DE/treestyletab/treestyletab.dtd b/locale/de-DE/treestyletab/treestyletab.dtd
index 81386b51..26ef9e73 100644
--- a/locale/de-DE/treestyletab/treestyletab.dtd
+++ b/locale/de-DE/treestyletab/treestyletab.dtd
@@ -120,6 +120,10 @@ auf die Ebene des geschlossenen Tabs verschieben">
 <!ENTITY config.insertNewChildAt.first "Oben im Zweig einfügen">
 <!ENTITY config.insertNewChildAt.last "Unten im Zweig einfügen">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 
diff --git a/locale/en-US/treestyletab/treestyletab.dtd b/locale/en-US/treestyletab/treestyletab.dtd
index 183b92dc..b2aba72c 100644
--- a/locale/en-US/treestyletab/treestyletab.dtd
+++ b/locale/en-US/treestyletab/treestyletab.dtd
@@ -118,6 +118,10 @@
 <!ENTITY config.insertNewChildAt.first "Insert to the top of the sub tree, as the first child">
 <!ENTITY config.insertNewChildAt.last "Append to the last of the sub tree">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 
diff --git a/locale/es-ES/treestyletab/treestyletab.dtd b/locale/es-ES/treestyletab/treestyletab.dtd
index d61c4aab..24c72cb2 100644
--- a/locale/es-ES/treestyletab/treestyletab.dtd
+++ b/locale/es-ES/treestyletab/treestyletab.dtd
@@ -119,6 +119,10 @@
 <!ENTITY config.insertNewChildAt.first "Insertar arriba del todo en el árbol">
 <!ENTITY config.insertNewChildAt.last "Insertar abajo del todo en el árbol">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 
diff --git a/locale/it-IT/treestyletab/treestyletab.dtd b/locale/it-IT/treestyletab/treestyletab.dtd
index 54b14343..d51aaff1 100644
--- a/locale/it-IT/treestyletab/treestyletab.dtd
+++ b/locale/it-IT/treestyletab/treestyletab.dtd
@@ -119,6 +119,10 @@
 <!ENTITY config.insertNewChildAt.first "Inserisci all&apos;inizio del sottoalbero, come prima sottoscheda">
 <!ENTITY config.insertNewChildAt.last "Accoda all&apos;ultimo sottoalbero">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 
diff --git a/locale/ja/treestyletab/treestyletab.dtd b/locale/ja/treestyletab/treestyletab.dtd
index 2c23a140..e46c4c12 100644
--- a/locale/ja/treestyletab/treestyletab.dtd
+++ b/locale/ja/treestyletab/treestyletab.dtd
@@ -118,6 +118,10 @@
 <!ENTITY config.insertNewChildAt.first "サブツリーの最初の位置に挿入する">
 <!ENTITY config.insertNewChildAt.last "サブツリーの末尾に追加する">
 
+<!ENTITY config.useEffectiveTLD.caption  "同じサイトかどうかの判別方法">
+<!ENTITY config.useEffectiveTLD.enabled  "ドメイン名で判別する（aaa.example.comとbbb.example.comを同じサイトとして認識）">
+<!ENTITY config.useEffectiveTLD.disabled "ホスト名で判別する（aaa.example.comとbbb.example.comを別のサイトとして認識）">
+
 
 
 <!ENTITY context.openSelectionLinks.label     "選択したリンクをすべてタブで開く">
diff --git a/locale/pl-PL/treestyletab/treestyletab.dtd b/locale/pl-PL/treestyletab/treestyletab.dtd
index 1e4bd534..a641500d 100644
--- a/locale/pl-PL/treestyletab/treestyletab.dtd
+++ b/locale/pl-PL/treestyletab/treestyletab.dtd
@@ -118,6 +118,10 @@
 <!ENTITY config.insertNewChildAt.first "Wstaw jako pierwszą na górze drzewa">
 <!ENTITY config.insertNewChildAt.last "Wstaw na końcu drzewa">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 
diff --git a/locale/ru-RU/treestyletab/treestyletab.dtd b/locale/ru-RU/treestyletab/treestyletab.dtd
index 9a8aa293..323f9813 100755
--- a/locale/ru-RU/treestyletab/treestyletab.dtd
+++ b/locale/ru-RU/treestyletab/treestyletab.dtd
@@ -119,6 +119,10 @@
 <!ENTITY config.insertNewChildAt.first "Вставлять первой в начало поддерева">
 <!ENTITY config.insertNewChildAt.last "Добавлять в конце поддерева">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 
diff --git a/locale/zh-CN/treestyletab/treestyletab.dtd b/locale/zh-CN/treestyletab/treestyletab.dtd
index 5f649224..910ab617 100644
--- a/locale/zh-CN/treestyletab/treestyletab.dtd
+++ b/locale/zh-CN/treestyletab/treestyletab.dtd
@@ -119,6 +119,10 @@
 <!ENTITY config.insertNewChildAt.first "插入到子树顶部，成为首个子标签">
 <!ENTITY config.insertNewChildAt.last "添加到子树的最后">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 
diff --git a/locale/zh-TW/treestyletab/treestyletab.dtd b/locale/zh-TW/treestyletab/treestyletab.dtd
index 5bdf6fbf..70f691d0 100644
--- a/locale/zh-TW/treestyletab/treestyletab.dtd
+++ b/locale/zh-TW/treestyletab/treestyletab.dtd
@@ -116,6 +116,10 @@
 <!ENTITY config.insertNewChildAt.first "插入到子樹的開端">
 <!ENTITY config.insertNewChildAt.last "新增到子樹的末端">
 
+<!ENTITY config.useEffectiveTLD.caption  "Detecting method for &quot;same website&quot;">
+<!ENTITY config.useEffectiveTLD.enabled  "by Domain name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are same website)">
+<!ENTITY config.useEffectiveTLD.disabled "by Host name (&quot;aaa.example.com&quot; and &quot;bbb.example.com&quot; are different website)">
+
 
 
 <!ENTITY context.openSelectionLinks.label     "用新分頁開啟所有選取的鏈結">