diff --git a/modules/utils.js b/modules/utils.js
index 6fac3313..f6bc13b5 100644
--- a/modules/utils.js
+++ b/modules/utils.js
@@ -1261,12 +1261,11 @@ var TreeStyleTabUtils = {
 		if (!aTab) return null;
 		var id = aTab.getAttribute(this.kID);
 		if (!id) return null; // not initialized yet
-		var tab = this.evaluateXPath(
-				'parent::*/child::xul:tab[contains(concat("|", @'+this.kCHILDREN+', "|"), "|'+id+'|")]',
+		return this.evaluateXPath(
+				'preceding-sibling::xul:tab[contains(concat("|", @'+this.kCHILDREN+', "|"), "|'+id+'|")]',
 				aTab,
 				Ci.nsIDOMXPathResult.FIRST_ORDERED_NODE_TYPE
 			).singleNodeValue;
-		return tab == aTab ? null : tab ;
 	},
  
 	getRootTab : function TSTUtils_getRootTab(aTab) /* PUBLIC API */