code: public <H extends EventHandler> HandlerRegistration registerDomHandler(final H handler, DomEvent.Type<H> type) {
  
          return addDomHandler(handler, type);
      }
docs: Adds a new event handler to the widget.<p>
  
  This method is used because we want the select box to register some event handlers on this widget,
  but we can't use {@link com.google.gwt.user.client.ui.Widget#addDomHandler} directly, since it's both protected
  and final.
  
  @param <H> the event type
  @param handler the new event handler
  @param type the event type object
  
  @return the HandlerRegistration for removing the event handler