static int withLeftAndRightMargin_defaultWidth = 6;

static JPanel withLeftAndRightMargin(Component c) {
  ret withLeftAndRightMargin(withLeftAndRightMargin_defaultWidth, c);
}

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