static JFrame renewFrame(final JFrame frame) {
  ret (JFrame) swing(func {
    Container content = frame.getContentPane();
    JFrame frame2 = new JFrame(frame.getTitle());
    frame2.setBounds(frame.getBounds());
    pcall { frame2.setIcon(frame.getIcon()); }
    frame.setContentPane(new JPanel);
    frame2.setContentPane(content);
    frame2.setVisible(true);
    frame.dispose();
    ret frame2;
  });
}