public class TestAddon {
	
	private EventHandler testHandler;
	@PostConstruct
	public void pc(IEventBroker eventBroker)
	{
		testHandler = new EventHandler() {
			
			@Override
			public void handleEvent(Event event) {
				Object part = event.getProperty(UIEvents.EventTags.ELEMENT);
				boolean tbr =(Boolean) event.getProperty(UIEvents.EventTags.NEW_VALUE);
				if (part instanceof MPart){
					System.out.println("Part "+((MPart)part).getElementId()+" is "+(!tbr?"NOT":"")+" visible");
				}
			}
		};
		eventBroker.subscribe(UIEvents.UIElement.TOPIC_TOBERENDERED, testHandler);
	}
	
	//....................
}