      */
     private function dataGrid_keyboardDownHandler(event:KeyboardEvent):void
     {
-        if (!dataGrid.editable)
+        if (!dataGrid.editable || dataGrid.selectionMode == GridSelectionMode.NONE)
             return;
         
         if (event.isDefaultPrevented())

    
    /**
     *  @private
     *  Used to restore the value of DataGrid's hasFocusableChildren.
     */
    private var saveDataGridHasFocusableChildren:Boolean;

        if (itemEditorInstance || editedItemRenderer)
        {
            dataGrid.endItemEditorSession();
            dataGrid.setFocus();
        }
    }
    
