@Override
  protected RadComponent findOverlappingComponent(final int startRow, final int startCol, final int rowSpan, final int colSpan) {
    if (rowSpan == 1 && colSpan == 1) {
      // we will replace the overlapping component, so it shouldn't prevent drop
      return null;
    }
    return super.findOverlappingComponent(startRow, startCol, rowSpan, colSpan);
  }
@Override
  protected RadComponent findOverlappingComponent(final int startRow, final int startCol, final int rowSpan, final int colSpan)