code: public JsHandlerRegistration addFeatureSelectionHandler(final FeatureSelectedHandler selectedHandler,
  			final FeatureDeselectedHandler deselectedHandler) {
  		if (((MapImpl) map).getMapWidget().getMapModel().isInitialized()) {
  			return addFeatureSelectionHandler2(selectedHandler, deselectedHandler);
  		}
  		final CallbackHandlerRegistration callbackRegistration = new CallbackHandlerRegistration();
  		((MapImpl) map).getMapWidget().getMapModel().addMapModelChangedHandler(new MapModelChangedHandler() {
  
  			public void onMapModelChanged(MapModelChangedEvent event) {
  				JsHandlerRegistration temp = addFeatureSelectionHandler2(selectedHandler, deselectedHandler);
  				callbackRegistration.setRegistration(temp);
  			}
  		});
  		return callbackRegistration;
  	}
docs: Add a handler for feature selection.