         if (!validateCellRegion(rowIndex, columnIndex, 1, 1))
             return false;
         
-        addCellRegion(rowIndex, columnIndex, 1, 1);
+        internalAddCell(rowIndex, columnIndex);
         
         return true;
     }

        if (!validateCellRegion(rowIndex, columnIndex, rowCount, columnCount))
            return false;
        
        const bottom:int = rowIndex + rowCount;
        const right:int = columnIndex + columnCount;
        

        if (!validateIndex(rowIndex))
            return false;
    
        internalSetCellRegion(rowIndex);
                
        return true;
    }
