static JPanel hstack(O... parts) {
  JPanel panel = new JPanel(new GridBagLayout);
  new GridBagConstraints gbc;
  gbc.weighty = 1;
  gbc.fill = GridBagConstraints.VERTICAL;
  gbc.gridheight = GridBagConstraints.REMAINDER;
  smartAddWithLayout(panel, gbc, parts);
  gbc.weightx = 1;
  panel.add(jrigid(), gbc);
  ret panel;
}