         return " ";
     }
 
+    /**
+     * @private
+     */
     protected function deriveComplexColumnData( data:Object ):Object 
     {
         var currentRef:Object = data;

            }
            
        }
		else
			hasComplexFieldName = false;

        if (owner)
            owner.invalidateList();

        return currentRef;
    }

    /**
     * @private
     */
    protected function complexColumnSortCompare( obj1:Object, obj2:Object ):int 
    {
        if ( !obj1 && !obj2 )
