         const colOffset:int = visibleColumnIndices.indexOf(columnIndex);
         if ((rowOffset == -1) || (colOffset == -1))
             return -1;
-        
+
         const index:int = (rowOffset * visibleColumnIndices.length) + colOffset;
         return index;
     }

        visibleRowIndices = newVisibleRowIndices;
        visibleColumnIndices = newVisibleColumnIndices;
    }

    /**
     *  @private

        var cellX:Number = startCellX;
        var cellY:Number = startCellY;
        var availableHeight:Number = height;
        
        for (rowIndex = startRowIndex; (availableHeight > 0) && (rowIndex >= 0) && (rowIndex < rowCount); rowIndex++)
        {
            newVisibleRowIndices.push(rowIndex);
