public void handleEvent(Event event) {
			ModelChangeEvent e = (ModelChangeEvent) event;
			switch (e.eventType) {
			case Utility.EVENT_NEW_NODE:
			case Utility.EVENT_UPDATE_NODE:
			case Utility.EVENT_RELOAD:
			case Utility.EVENT_DEL_NODE:
			case Utility.EVENT_NEW_EDGE: {
				for (Control control : targetArea.getChildren()) {
					control.dispose();
				}
				targetArea.redraw();
				break;
			}
			}
		}