diff --git a/content/treestyletab/config.xul b/content/treestyletab/config.xul
index 6d454632..13c4501b 100644
--- a/content/treestyletab/config.xul
+++ b/content/treestyletab/config.xul
@@ -640,6 +640,9 @@
 <prefpane id="prefpane-tree" label="&config.tabs.tree;"
 	onpaneload="initTreePane();">
 	<preferences>
+		<preference id="extensions.treestyletab.autoCollapseExpandSubtreeOnAttach"
+			name="extensions.treestyletab.autoCollapseExpandSubtreeOnAttach"
+			type="bool"/>
 		<preference id="extensions.treestyletab.autoCollapseExpandSubtreeOnSelect"
 			name="extensions.treestyletab.autoCollapseExpandSubtreeOnSelect"
 			type="bool"/>
@@ -667,7 +670,11 @@
 			type="int"/>
 	</preferences>
 
+	<checkbox id="extensions.treestyletab.autoCollapseExpandSubtreeOnAttach-check"
+		preference="extensions.treestyletab.autoCollapseExpandSubtreeOnAttach"
+		label="&config.autoCollapseExpandSubtreeOnAttach;"/>
 	<checkbox id="extensions.treestyletab.autoCollapseExpandSubtreeOnSelect-check"
+
 		preference="extensions.treestyletab.autoCollapseExpandSubtreeOnSelect"
 		label="&config.autoCollapseExpandSubtreeOnSelect;"/>
 	<hbox align="center">
diff --git a/locale/da-DK/treestyletab/treestyletab.dtd b/locale/da-DK/treestyletab/treestyletab.dtd
index fa4f94ea..19d84128 100644
--- a/locale/da-DK/treestyletab/treestyletab.dtd
+++ b/locale/da-DK/treestyletab/treestyletab.dtd
@@ -130,6 +130,7 @@
 
 <!ENTITY config.tabs.tree "Træet">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "Udvid tilhørende træ når en fane vælges, og sammenfold automatisk de andre">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Ekskluder fokusflytning forårsaget af af aktuel fanes lukning">
 <!ENTITY config.collapseExpandSubtree.dblclick "Dobbeltklik på en fane for at sammenfolde/udvide træ">
diff --git a/locale/de-DE/treestyletab/treestyletab.dtd b/locale/de-DE/treestyletab/treestyletab.dtd
index 540c49a3..631852c6 100644
--- a/locale/de-DE/treestyletab/treestyletab.dtd
+++ b/locale/de-DE/treestyletab/treestyletab.dtd
@@ -130,6 +130,7 @@
 
 <!ENTITY config.tabs.tree "Verhalten">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "Nicht aktive Zweige zuklappen">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Keine Fokusänderung beim Schließen des aktiven Tabs">
 <!ENTITY config.collapseExpandSubtree.dblclick "Bei Doppelklick auf Tab untergeordneten Zweig auf- oder zuklappen">
diff --git a/locale/en-US/treestyletab/treestyletab.dtd b/locale/en-US/treestyletab/treestyletab.dtd
index 2d670530..e3bd0abf 100644
--- a/locale/en-US/treestyletab/treestyletab.dtd
+++ b/locale/en-US/treestyletab/treestyletab.dtd
@@ -116,6 +116,7 @@
 
 <!ENTITY config.tabs.tree "Tree">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "When a tab gets focus, expand its tree and collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Exclude focus moving caused by current tab closing">
 <!ENTITY config.collapseExpandSubtree.dblclick "Double-click on a tab to collapse/expand tree">
diff --git a/locale/es-ES/treestyletab/treestyletab.dtd b/locale/es-ES/treestyletab/treestyletab.dtd
index 1718a4e2..2cfee798 100644
--- a/locale/es-ES/treestyletab/treestyletab.dtd
+++ b/locale/es-ES/treestyletab/treestyletab.dtd
@@ -125,6 +125,7 @@
 
 <!ENTITY config.tabs.tree "Arbol">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!--ENTITY config.autoCollapseExpandSubtreeOnSelect "Colapsar otros árboles automáticamente cuando una pestaña es abierta o seleccionada"-->
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "Cuando una pestaña obtiene foco, expandir su árbol y colapsar los otros automáticamente">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Excluir movimiento de foco causado por el cierre de la pestaña en foco">
diff --git a/locale/fr-FR/treestyletab/treestyletab.dtd b/locale/fr-FR/treestyletab/treestyletab.dtd
index c9c4d786..4dcb062e 100644
--- a/locale/fr-FR/treestyletab/treestyletab.dtd
+++ b/locale/fr-FR/treestyletab/treestyletab.dtd
@@ -117,6 +117,7 @@
 
 <!ENTITY config.tabs.tree "Arborescence">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "Lorsqu'un onglet devient actif, déplier son arborescence et replier les autres automatiquement">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Exclure le changement d'activation par la fermeture de l'onglet actuel">
 <!ENTITY config.collapseExpandSubtree.dblclick "Double-cliquer sur un onglet pour replier/déplier l'arborescence">
diff --git a/locale/it-IT/treestyletab/treestyletab.dtd b/locale/it-IT/treestyletab/treestyletab.dtd
index 73fdcd24..78cf62b4 100644
--- a/locale/it-IT/treestyletab/treestyletab.dtd
+++ b/locale/it-IT/treestyletab/treestyletab.dtd
@@ -125,6 +125,7 @@
 
 <!ENTITY config.tabs.tree "Tree">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!--ENTITY config.autoCollapseExpandSubtreeOnSelect "Contrai automaticamente gli altri sottoalberi quando viene aperta o selezionata una scheda"-->
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "When a tab gets focus, expand his tree and collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Exclude focus moving caused by current tab closing">
diff --git a/locale/ja/treestyletab/treestyletab.dtd b/locale/ja/treestyletab/treestyletab.dtd
index 106d2799..3a21030c 100644
--- a/locale/ja/treestyletab/treestyletab.dtd
+++ b/locale/ja/treestyletab/treestyletab.dtd
@@ -117,6 +117,7 @@
 
 <!ENTITY config.tabs.tree "ツリー">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "新しいツリーが作られた時は、自動的に他のツリーを折り畳む">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "タブを切り替えた時は、フォーカスされたタブのツリーを自動的に展開して、他のツリーを折り畳む">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "現在のタブを閉じてタブのフォーカスが切り替わった場合は何もしない">
 
diff --git a/locale/pl/treestyletab/treestyletab.dtd b/locale/pl/treestyletab/treestyletab.dtd
index ec698c6f..5bf988d2 100644
--- a/locale/pl/treestyletab/treestyletab.dtd
+++ b/locale/pl/treestyletab/treestyletab.dtd
@@ -125,6 +125,7 @@
 
 <!ENTITY config.tabs.tree "Drzewo">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "Rozwijaj drzewo wybranej karty i zwijaj pozostałe">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Z wyjątkiem, gdy wybór się zmieni na skutek zamknięcia aktywnej karty">
 <!ENTITY config.collapseExpandSubtree.dblclick "Zwijaj/rozwijaj drzewo po dwukrotnym kliknięciu etykiety karty">
diff --git a/locale/ru/treestyletab/treestyletab.dtd b/locale/ru/treestyletab/treestyletab.dtd
index 25f301ec..7260f376 100755
--- a/locale/ru/treestyletab/treestyletab.dtd
+++ b/locale/ru/treestyletab/treestyletab.dtd
@@ -123,6 +123,7 @@
 
 <!ENTITY config.tabs.tree "Дерево">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "При выборе вкладки развернуть её дерево и автоматически свернуть остальные">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Исключая выбор вкладки после закрытия текущей вкладки">
 <!ENTITY config.collapseExpandSubtree.dblclick "Сворачивать/разворачивать дерево вкладок по двойному клику">
diff --git a/locale/sv-SE/treestyletab/treestyletab.dtd b/locale/sv-SE/treestyletab/treestyletab.dtd
index 273572dc..af8f9725 100644
--- a/locale/sv-SE/treestyletab/treestyletab.dtd
+++ b/locale/sv-SE/treestyletab/treestyletab.dtd
@@ -129,6 +129,7 @@
 
 <!ENTITY config.tabs.tree "Träd">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "När en flik får fokus, expandera dess träd och minimera andra träd automatiskt">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "Inaktivera flytt av fokus orsakad av att aktuell flik stängs">
 <!ENTITY config.collapseExpandSubtree.dblclick "Dubbelklicka på en flik för att minimera/expandera trädet">
diff --git a/locale/zh-CN/treestyletab/treestyletab.dtd b/locale/zh-CN/treestyletab/treestyletab.dtd
index 426efe0a..a5d581f8 100644
--- a/locale/zh-CN/treestyletab/treestyletab.dtd
+++ b/locale/zh-CN/treestyletab/treestyletab.dtd
@@ -129,6 +129,7 @@
 
 <!ENTITY config.tabs.tree "树状结构">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "某一标签获得焦点时，自动展开该标签子树并折叠其他标签树">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "当前标签关闭引起的焦点转移除外">
 <!ENTITY config.collapseExpandSubtree.dblclick "通过双击折叠/展开标签的子树">
diff --git a/locale/zh-TW/treestyletab/treestyletab.dtd b/locale/zh-TW/treestyletab/treestyletab.dtd
index 1e3c0a44..ac635307 100644
--- a/locale/zh-TW/treestyletab/treestyletab.dtd
+++ b/locale/zh-TW/treestyletab/treestyletab.dtd
@@ -117,6 +117,7 @@
 
 <!ENTITY config.tabs.tree "樹狀結構">
 
+<!ENTITY config.autoCollapseExpandSubtreeOnAttach "When a new tree appears, collapse others automatically">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect "切換分頁時，自動展開該子樹，並摺疊無關的分頁">
 <!ENTITY config.autoCollapseExpandSubtreeOnSelect.onCurrentTabRemove "不包括關閉當前分頁造成的切換">