static int withBottomMargin_defaultWidth = 6;

static JPanel withBottomMargin(Component c) {
  ret withBottomMargin(withBottomMargin_defaultWidth, c);
}

static JPanel withBottomMargin(final int w, final Component c) {
  ret swing(func -> JPanel {
    JPanel p = new JPanel(new BorderLayout);
    p.setBorder(BorderFactory.createEmptyBorder(0, 0, w, 0));
    p.add(c);
    ret p;
  }
}