repaint();
if (getRowCount() < 2) return;  int y_gap = rowMargin; int y0 = (getRowHeight() + y_gap) * (event.getFirstIndex()); int yn = (getRowHeight() + y_gap) * (event.getLastIndex()+1); repaint(0, y0, getWidth(), yn-y0);
  public void valueChanged (ListSelectionEvent event)  {    repaint();  }