         const newColumns:IList = _columns;
         if (newColumns)
         {
-            newColumns.addEventListener(CollectionEvent.COLLECTION_CHANGE, columns_collectionChangeHandler, false, 0, true);            
+            newColumns.addEventListener(CollectionEvent.COLLECTION_CHANGE, columns_collectionChangeHandler, false, 0, true);
             for (index = 0; index < newColumns.length; index++)
             {
                 var newColumn:GridColumn = GridColumn(newColumns.getItemAt(index));

        invalidateDisplayList();        
    } 
    
    //--------------------------------------------------------------------------
    //
    //  Methods

                
            case CollectionEventKind.UPDATE:
            {
                // column may have changed visiblity                
                const itemsLength:int = event.items.length;
                var itemsLeft:int = count;
                var pcEvent:PropertyChangeEvent;
                
                for (i = 0; i < itemsLength; i++)
                {
                    pcEvent = event.items[i] as PropertyChangeEvent;
                    if (pcEvent && pcEvent.property == "visible")
                    {
                        columns_visibleChangedHandler(pcEvent);
                        itemsLeft--;
                    }
                }
                
                // return if all were visible property changes
                if (itemsLeft == 0)
                    return;
                
                break;
            }
                
