}
});
AlphaPicker c2 = new AlphaPicker();
c2.setAlpha(stop.getColor().getAlpha());
c2.onAlphaSelected(new Callback<ChangedEvent>() {
public void call(ChangedEvent changedEvent) throws Exception {
Double d = (Double) changedEvent.getValue();
stop.setColor(stop.getColor().deriveWithAlpha(d));
refresh();
}