Fixing a stupid and obvious mistake I made with the last check-in for bug 341047

toolkit/content/widgets/scrollbox.xml

@@ -174,6 +174,7 @@
             if (childNodes.length > 0)
               this.ensureElementIsVisible(childNodes[0]);
           }
+        }
         catch(e) {
           this._scrollButtonUp.collapsed = false;
           this._scrollButtonDown.collapsed = false;