diff --git a/modules/browser.js b/modules/browser.js
index 35662b18..d66b03fd 100644
--- a/modules/browser.js
+++ b/modules/browser.js
@@ -5718,6 +5718,9 @@ TreeStyleTabBrowser.prototype = {
 
 		this.needRestoreTree = false;
 
+		if (this.useTMPSessionAPI && this.getPref('extensions.tabmix.sessions.manager'))
+			return;
+
 		var level = this.getTreePref('restoreTree.level');
 		if (
 			level <= this.kRESTORE_TREE_LEVEL_NONE ||
diff --git a/modules/utils.js b/modules/utils.js
index 424237d8..85aff23d 100644
--- a/modules/utils.js
+++ b/modules/utils.js
@@ -1110,15 +1110,7 @@ var TreeStyleTabUtils = {
 		}, this);
 	},
  
-	_useTMPSessionAPI : false, 
-	get useTMPSessionAPI()
-	{
-		return this._useTMPSessionAPI && this.getPref('extensions.tabmix.sessions.manager');
-	},
-	set useTMPSessionAPI(aValue)
-	{
-		return this._useTMPSessionAPI = !!aValue;
-	},
+	useTMPSessionAPI : false, 
  
 	kTMP_SESSION_DATA_PREFIX : 'tmp-session-data-',