code: private void trackListeners(final BundleContext bundleContext) {
  		final ServiceTracker<EventListener, ListenerWebElement> listenerTracker = ListenerTracker
  				.createTracker(extenderContext, bundleContext);
  
  		listenerTracker.open();
  		trackers.add(0, listenerTracker);
  
  		// FIXME needed?
  		final ServiceTracker<ListenerMapping, ListenerMappingWebElement> listenerMappingTracker = ListenerMappingTracker
  				.createTracker(extenderContext, bundleContext);
  
  		listenerMappingTracker.open();
  		trackers.add(0, listenerMappingTracker);
  	}
docs: Track listeners.
  
  @param bundleContext the BundleContext associated with this bundle