diff --git a/content/treestyletab/config.js b/content/treestyletab/config.js
index db33c8f5..349bfb5b 100644
--- a/content/treestyletab/config.js
+++ b/content/treestyletab/config.js
@@ -223,12 +223,10 @@ function onChangeTabbarPosition()
 
 	var horizontalElements = [
 		'maxTreeLevel-horizontal',
-		'extensions.treestyletab.allowSubtreeCollapseExpand.horizontal-check',
 		'fixedTabbar-horizontal'
 	];
 	var verticalElements = [
 		'maxTreeLevel-vertical',
-		'extensions.treestyletab.allowSubtreeCollapseExpand.vertical-check',
 		'fixedTabbar-vertical'
 	];
 	if (pos == 'left' || pos == 'right') {
diff --git a/content/treestyletab/config.xul b/content/treestyletab/config.xul
index c85a27d9..09ca555e 100644
--- a/content/treestyletab/config.xul
+++ b/content/treestyletab/config.xul
@@ -45,12 +45,6 @@
 		<preference id="extensions.treestyletab.maxTreeLevel.vertical"
 			name="extensions.treestyletab.maxTreeLevel.vertical"
 			type="int"/>
-		<preference id="extensions.treestyletab.allowSubtreeCollapseExpand.horizontal"
-			name="extensions.treestyletab.allowSubtreeCollapseExpand.horizontal"
-			type="bool"/>
-		<preference id="extensions.treestyletab.allowSubtreeCollapseExpand.vertical"
-			name="extensions.treestyletab.allowSubtreeCollapseExpand.vertical"
-			type="bool"/>
 		<preference id="extensions.treestyletab.tabbar.invertClosebox"
 			name="extensions.treestyletab.tabbar.invertClosebox"
 			type="bool"/>
@@ -161,14 +155,6 @@
 				preference="extensions.treestyletab.tabbar.narrowScrollbar"
 				label="&config.tabbar.narrowScrollbar;"/>
 		</hbox>
-		<hbox align="center">
-			<checkbox id="extensions.treestyletab.allowSubtreeCollapseExpand.horizontal-check"
-				preference="extensions.treestyletab.allowSubtreeCollapseExpand.horizontal"
-				label="&config.allowSubtreeCollapseExpand;"/>
-			<checkbox id="extensions.treestyletab.allowSubtreeCollapseExpand.vertical-check"
-				preference="extensions.treestyletab.allowSubtreeCollapseExpand.vertical"
-				label="&config.allowSubtreeCollapseExpand;"/>
-		</hbox>
 		<hbox id="maxTreeLevel-horizontal"
 			align="center">
 			<checkbox id="maxTreeLevel-checkbox-horizontal"
diff --git a/defaults/preferences/treestyletab.js b/defaults/preferences/treestyletab.js
index 70390fde..fbd38228 100644
--- a/defaults/preferences/treestyletab.js
+++ b/defaults/preferences/treestyletab.js
@@ -183,13 +183,6 @@ pref("extensions.treestyletab.tabbar.fixed.autoCancelOnDrop", true);
  */
 pref("extensions.treestyletab.enableSubtreeIndent.allTabsPopup", true);
 
-/**
- * These prefs activate "collaable tree" feature for horizontal and
- * vertical tab bar.
- */
-pref("extensions.treestyletab.allowSubtreeCollapseExpand.horizontal", false);
-pref("extensions.treestyletab.allowSubtreeCollapseExpand.vertical",   true);
-
 /**
  * Activates "stacked tabs" in the horizontal tab bar.
  * It is very hard to know how many tabs are collapsed in a horizontal tab bar.
diff --git a/locale/cs/treestyletab/treestyletab.dtd b/locale/cs/treestyletab/treestyletab.dtd
index 422f7c23..b33e9d2d 100644
--- a/locale/cs/treestyletab/treestyletab.dtd
+++ b/locale/cs/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent "Odsazovat panely">
 <!ENTITY config.maxTreeLevel.before "až do">
 <!ENTITY config.maxTreeLevel.after  "úrovní">
-<!ENTITY config.allowSubtreeCollapseExpand  "Umožnit sbalení/rozbalení stromu panelů">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/da-DK/treestyletab/treestyletab.dtd b/locale/da-DK/treestyletab/treestyletab.dtd
index c03a1dbe..f9404d74 100644
--- a/locale/da-DK/treestyletab/treestyletab.dtd
+++ b/locale/da-DK/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent "Indryk faner">
 <!ENTITY config.maxTreeLevel.before "op til">
 <!ENTITY config.maxTreeLevel.after "niveauer">
-<!ENTITY config.allowSubtreeCollapseExpand "Tillad sammenfold/udvid fanetræ">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/de-DE/treestyletab/treestyletab.dtd b/locale/de-DE/treestyletab/treestyletab.dtd
index dae26df9..01efcb8c 100644
--- a/locale/de-DE/treestyletab/treestyletab.dtd
+++ b/locale/de-DE/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent          "Tabs einrücken">
 <!ENTITY config.maxTreeLevel.before          "bis">
 <!ENTITY config.maxTreeLevel.after           "Level">
-<!ENTITY config.allowSubtreeCollapseExpand   "Auf- und Einklappen von Zweigen erlauben">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px Höhe">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/en-US/treestyletab/treestyletab.dtd b/locale/en-US/treestyletab/treestyletab.dtd
index 504090d7..3e4e1a81 100644
--- a/locale/en-US/treestyletab/treestyletab.dtd
+++ b/locale/en-US/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent "Indent tabs">
 <!ENTITY config.maxTreeLevel.before "until">
 <!ENTITY config.maxTreeLevel.after  "level(s)">
-<!ENTITY config.allowSubtreeCollapseExpand  "Allow to collapse/expand tree of tabs">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/es-ES/treestyletab/treestyletab.dtd b/locale/es-ES/treestyletab/treestyletab.dtd
index 4fb2642c..f4894c9d 100644
--- a/locale/es-ES/treestyletab/treestyletab.dtd
+++ b/locale/es-ES/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent         "Añadir margen a las pestañas">
 <!ENTITY config.maxTreeLevel.before "hasta">
 <!ENTITY config.maxTreeLevel.after  "nivel(es)">
-<!ENTITY config.allowSubtreeCollapseExpand  "Permitir colapsar/expandir los sub-árboles de las pestañas">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/fr-FR/treestyletab/treestyletab.dtd b/locale/fr-FR/treestyletab/treestyletab.dtd
index 5e679978..a52e8adb 100644
--- a/locale/fr-FR/treestyletab/treestyletab.dtd
+++ b/locale/fr-FR/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent         "Indenter les onglets">
 <!ENTITY config.maxTreeLevel.before "jusqu'à">
 <!ENTITY config.maxTreeLevel.after  "niveau(x)">
-<!ENTITY config.allowSubtreeCollapseExpand  "Autoriser le repliage/dépliage des arborescences d'onglets">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/it-IT/treestyletab/treestyletab.dtd b/locale/it-IT/treestyletab/treestyletab.dtd
index b8949cd6..73e24b68 100644
--- a/locale/it-IT/treestyletab/treestyletab.dtd
+++ b/locale/it-IT/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent         "Indenta sottoschede">
 <!ENTITY config.maxTreeLevel.before "until">
 <!ENTITY config.maxTreeLevel.after  "level(s)">
-<!ENTITY config.allowSubtreeCollapseExpand  "Permetti di contrarre/espandere sottoalberi delle schede">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/ja/treestyletab/treestyletab.dtd b/locale/ja/treestyletab/treestyletab.dtd
index 90626b2a..a4bca36c 100644
--- a/locale/ja/treestyletab/treestyletab.dtd
+++ b/locale/ja/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent "ツリーをインデント表示する">
 <!ENTITY config.maxTreeLevel.before "（">
 <!ENTITY config.maxTreeLevel.after  "階層まで）">
-<!ENTITY config.allowSubtreeCollapseExpand  "ツリーを折りたためるようにする">
 <!ENTITY config.tabbarSize.before-horizontal "高さ:">
 <!ENTITY config.tabbarSize.after-horizontal  "ピクセル">
 <!ENTITY config.tabbarSize.before-vertical   "幅:">
diff --git a/locale/pl/treestyletab/treestyletab.dtd b/locale/pl/treestyletab/treestyletab.dtd
index 27d47dd5..7fba5cc1 100644
--- a/locale/pl/treestyletab/treestyletab.dtd
+++ b/locale/pl/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent         "Stosuj wcięcia">
 <!ENTITY config.maxTreeLevel.before "until">
 <!ENTITY config.maxTreeLevel.after  "level(s)">
-<!ENTITY config.allowSubtreeCollapseExpand  "Zezwalaj na zwijanie/rozwijanie drzewa kart">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/ru/treestyletab/treestyletab.dtd b/locale/ru/treestyletab/treestyletab.dtd
index ed5bbb55..8d671d57 100755
--- a/locale/ru/treestyletab/treestyletab.dtd
+++ b/locale/ru/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent         "Отступы вкладок">
 <!ENTITY config.maxTreeLevel.before "пока уровней меньше">
 <!ENTITY config.maxTreeLevel.after  "">
-<!ENTITY config.allowSubtreeCollapseExpand  "Разрешить сворачивать/разворачивать поддеревья вкладок">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "пикселей в высоту">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/sv-SE/treestyletab/treestyletab.dtd b/locale/sv-SE/treestyletab/treestyletab.dtd
index 4f16fd60..f14928f9 100644
--- a/locale/sv-SE/treestyletab/treestyletab.dtd
+++ b/locale/sv-SE/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent "Gör indrag av flikar">
 <!ENTITY config.maxTreeLevel.before "t.o.m. den">
 <!ENTITY config.maxTreeLevel.after  "nivån">
-<!ENTITY config.allowSubtreeCollapseExpand  "Tillåt att flikträd kan minimeras/expanderas">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/zh-CN/treestyletab/treestyletab.dtd b/locale/zh-CN/treestyletab/treestyletab.dtd
index 9cdd9227..0020efa5 100644
--- a/locale/zh-CN/treestyletab/treestyletab.dtd
+++ b/locale/zh-CN/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent         "缩进标签">
 <!ENTITY config.maxTreeLevel.before "最多">
 <!ENTITY config.maxTreeLevel.after  "层">
-<!ENTITY config.allowSubtreeCollapseExpand  "允许折叠/展开标签子树">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">
diff --git a/locale/zh-TW/treestyletab/treestyletab.dtd b/locale/zh-TW/treestyletab/treestyletab.dtd
index bd15c9e2..05727c7c 100644
--- a/locale/zh-TW/treestyletab/treestyletab.dtd
+++ b/locale/zh-TW/treestyletab/treestyletab.dtd
@@ -19,7 +19,6 @@
 <!ENTITY config.enableSubtreeIndent         "縮進分頁">
 <!ENTITY config.maxTreeLevel.before "（最多">
 <!ENTITY config.maxTreeLevel.after  "層）">
-<!ENTITY config.allowSubtreeCollapseExpand  "允許摺疊 / 展開樹狀子目錄">
 <!ENTITY config.tabbarSize.before-horizontal ":">
 <!ENTITY config.tabbarSize.after-horizontal  "px height">
 <!ENTITY config.tabbarSize.before-vertical   ":">