         element.visible = false;
     }
     
+    //----------------------------------
+    //  columnHeaderGroup
+    //----------------------------------
+    
+    /**
+     *  @private
+     */
     private function get columnHeaderGroup():GridColumnHeaderGroup
     {
         return target as GridColumnHeaderGroup;
     }
     
+    //----------------------------------
+    //  grid
+    //----------------------------------
+    
+    /**
+     *  @private
+     */
     private function get grid():Grid
     {
         const chg:GridColumnHeaderGroup = columnHeaderGroup;


        // initialize the renderer
        
        renderer.column = column;
        renderer.label = column.headerText;
        
        // layout the renderer


    
    /**
     *  @private
     */
    private function initializeItemRenderer(renderer:IGridItemRenderer,
                                            columnIndex:int,
                                            column:GridColumn,
                                            visible:Boolean=true):void
    {
        renderer.visible = visible;
        renderer.column = column;
        renderer.label = column.headerText;
        
        const columnHeaderGroup:GridColumnHeaderGroup = columnHeaderGroup;
        renderer.hovered = columnIndex == columnHeaderGroup.hoverColumnIndex;
        renderer.down = columnIndex == columnHeaderGroup.downColumnIndex;
    }
    
    /**
     *  @private
     *  Let the allocateGridElement() caller know if the returned element was 
     *  created or recycled.
     */
