static int withTopAndBottomMargin_defaultWidth = 6;

static JPanel withTopAndBottomMargin(Component c) {
  ret withTopAndBottomMargin(withTopAndBottomMargin_defaultWidth, withTopAndBottomMargin_defaultWidth, c);
}

static JPanel withTopAndBottomMargin(int topMargin, int bottomMargin, Component c) {
  ret swing(-> {
    JPanel p = new JPanel(new BorderLayout);
    int w = withTopAndBottomMargin_defaultWidth;
    p.setBorder(BorderFactory.createEmptyBorder(topMargin, 0, bottomMargin, 0));
    p.add(c);
    ret p;
  });
}

Began life as a copy of #1004959