         if ((visibleRowIndices == null) || (visibleColumnIndices == null))
             return -1;
         
-        // TBD(hmuller) - binary search would be faster than indexOf()
+        // TODO (hmuller) - binary search would be faster than indexOf()
         
         const rowOffset:int = visibleRowIndices.indexOf(rowIndex);
         const colOffset:int = visibleColumnIndices.indexOf(columnIndex);

        
        const x:Number = bounds.x;
        const width:Number = bounds.width;
        const y:Number = bounds.bottom; // TBD: should center on gap here.
        layoutGridElement(separator, x, y, width, height);
    }
    

        newIndices:Vector.<int>, 
        lastIndex:int):void
    {
        // TODO(hmuller): rewrite this, should be one pass (no indexOf)
        for (var i:int = 0; i < elements.length; i++)
        {
            const offset:int = newIndices.indexOf(oldIndices[i]);
