window.add("Center", clock);
window.setSize(clock.getSize());
// create an ImageRegion from the background image
// so we can use a rounded clock
ImageRegion region = new ImageRegion(back);
NativeSkin.getInstance().setWindowRegion(window, region, true);
// A clock should always be on top of other windows
NativeSkin.getInstance().setAlwaysOnTop(window, true);