 [ExcludeClass]
 
 /**
- *  TBD
+ *  @private
+ *  A virtual two dimensional layout for the Grid class.   This is not a general purpose layout,
+ *  it's only intended to be use with Grid.
  */
 public class GridLayout extends LayoutBase
 {

            startTime = getTimer();
        
        const validatingElt:IInvalidating = renderer as IInvalidating;
        if (renderer is IUITextField)  // TBD(hmuller) distinguish this special case differently
        {
            if (!isNaN(width) || !isNaN(height)) 
                renderer.setLayoutBoundsSize(width, height);

        const r:Rectangle = visibleItemRenderersBounds;
        const width:Number = separator.getPreferredBoundsWidth();
        const height:Number = Math.max(r.height, visibleGridBounds.height); 
        const x:Number = gridDimensions.getCellX(0, columnIndex) + gridDimensions.getColumnWidth(columnIndex); // TODO (hmuller): should center on gap here.
        const y:Number = r.y;
        layoutGridElement(separator, x, y, width, height);
    }
