protected Point getTableLocationForEvent(DropTargetDropEvent dropTargetDropEvent) {
   Point dropTargetPoint = dropTargetDropEvent.getLocation();
   int column = _underlyingTable.columnAtPoint(dropTargetPoint);
   int row = _underlyingTable.rowAtPoint(dropTargetPoint);
   if ((row < 0) || (column < 0)) {
     return null;
   }
   return new Point(row, column);
 }