diff --git a/toolkit/content/widgets/scrollbox.xml b/toolkit/content/widgets/scrollbox.xml
index 278ebcb21a4a..ea5f90cc0bba 100644
--- a/toolkit/content/widgets/scrollbox.xml
+++ b/toolkit/content/widgets/scrollbox.xml
@@ -352,8 +352,13 @@
 
       <method name="_getScrollableElements">
         <body><![CDATA[
-          var nodes = this.hasChildNodes() ?
-                        this.childNodes : document.getBindingParent(this).childNodes;
+          var nodes = this.childNodes;
+          if (nodes.length == 1 &&
+              nodes[0].localName == "children" &&
+              nodes[0].namespaceURI == "http://www.mozilla.org/xbl") {
+            nodes = document.getBindingParent(this).childNodes;
+          }
+
           return Array.filter(nodes, this._canScrollToElement, this);
         ]]></body>
       </method>
