static <A extends AbstractButton> A setHorizontalMargin(final int margin, final A a) {
  swing {
    Insets i = a.getMargin(); 
    a.setMargin(new Insets(i.top, margin, i.bottom, margin));
  }
  ret a;
}

static <A extends AbstractButton> A setHorizontalMargin(A a, int margin) {
  ret setHorizontalMargin(margin, a);
}