code: public boolean removeListener(ListenerController listenerController) {
  		if (listenerController != null && listeners.containsKey(listenerController)) {
  			List<HandlerRegistration> registrations = listeners.get(listenerController);
  			for (HandlerRegistration registration : registrations) {
  				registration.removeHandler();
  			}
  			listeners.remove(listenerController);
  			return true;
  		}
  		return false;
  	}
docs: Remove an existing listener controller from this widget. These listeners passively listen to mouse events on the
  map. They do not interfere with these events.
  
  @param listenerController
  The existing listener controller to remove.
  @return Returns true if removal was successful, false otherwise (i.e. if it could not be found).
  @since 1.8.0