--- a/suite/common/history/tree.xml
+++ b/suite/common/history/tree.xml
@@ -44,21 +44,21 @@
         ]]></getter>
         <setter><![CDATA[
           return this.treeBoxObject.view = val;
         ]]></setter>
       </property>
 
       <property name="sortingMode" readonly="true">
         <getter><![CDATA[
-          try {
+          var result = this.getResult();
+          if (result)
             // If we have a result then simply return its sorting mode.
-            return this.view.QueryInterface(Components.interfaces.nsINavHistoryResultViewer).result.sortingMode;
-          }
-          catch (e) {
+            return result.sortingMode;
+          else {
             // Find the sorted column from the persisted attributes.
             const NHQO = Components.interfaces.nsINavHistoryQueryOptions;
             var sortedColumn = this.columns.getSortedColumn();
             if (!sortedColumn)
               return NHQO.SORT_BY_NONE;
 
             var sortDescending =
               sortedColumn.element.getAttribute("sortDirection") != "ascending";