// component can be a custom-painted JComponent
static JWindow showAlwaysOnTopTranslucentWindow(Rect bounds, Color backgroundWithAlpha, JComponent component default null) {
  ret swing(() -> {
    JWindow f = makeAlwaysOnTopTranslucentWindow(bounds, backgroundWithAlpha, component);
    f.setVisible(true);
    vmBus_send newAlwaysOnTopWindow(f);
    ret f;
  });
}