diff --git a/content/treestyletab/treestyletab.js b/content/treestyletab/treestyletab.js
index fad32965..ff81bbe9 100644
--- a/content/treestyletab/treestyletab.js
+++ b/content/treestyletab/treestyletab.js
@@ -140,6 +140,8 @@ var TreeStyleTabService = {
 	
 	readyToOpenChildTab : function(aFrameOrTabBrowser, aMultiple, aInsertBefore) 
 	{
+		if (!this.getTreePref('autoAttachNewTabsAsChildren')) return;
+
 		var frame = this.getFrameFromTabBrowserElements(aFrameOrTabBrowser);
 		if (!frame) return;
 
@@ -153,6 +155,8 @@ var TreeStyleTabService = {
  
 	readyToOpenNewTabGroup : function(aFrameOrTabBrowser) 
 	{
+		if (!this.getTreePref('autoAttachNewTabsAsChildren')) return;
+
 		var frame = this.getFrameFromTabBrowserElements(aFrameOrTabBrowser);
 		if (!frame) return;
 
diff --git a/defaults/preferences/treestyletab.js b/defaults/preferences/treestyletab.js
index a205faea..86251dc9 100644
--- a/defaults/preferences/treestyletab.js
+++ b/defaults/preferences/treestyletab.js
@@ -48,6 +48,7 @@ pref("extensions.treestyletab.autoCollapseExpandSubTreeOnSelect",      true);
 pref("extensions.treestyletab.collapseExpandSubTree.dblclick",         false);
 pref("extensions.treestyletab.autoExpandSubTreeOnAppendChild",         true);
 pref("extensions.treestyletab.attachChildrenToGrandParentOnRemoveTab", true);
+pref("extensions.treestyletab.autoAttachNewTabsAsChildren", true);
 // 0 = default, 1 = only visible tabs
 pref("extensions.treestyletab.focusMode", 1);