static <A extends JSpinner> A onChange(A spinner, O r) {
  swing { spinner.addChangeListener(changeListener(r)); }
  ret spinner;
}

static <A extends AbstractButton> A onChange(A b, O r) {
  swing { b.addItemListener(itemListener(r)); }
  ret b;
}

static void onChange(JTextComponent tc, O r) {
  onUpdate(tc, r);
}

static <A extends JSlider> A onChange(A slider, fO r) {
  swing { slider.addChangeListener(changeListener(r)); }
  ret slider;
}

static JComboBox onChange(JComboBox cb, fO r) {
  if (isEditableComboBox(cb))
    onChange(textFieldFromComboBox(cb), r);
  else
    onSelectedItem(cb, voidfunc(S s) { callF(r) });
  ret cb;
}