if (handler != null) {
DOM.sinkEvents(DomHelper.castToOld(implNodelet), MOUSE_LISTENER_EVENTS);
DOM.setEventListener(DomHelper.castToOld(implNodelet), new EventListener() {
@Override
public void onBrowserEvent(Event event) {
handler.onEvent(element, event);
}
});
} else {
removeListener(DomHelper.castToOld(implNodelet));
}