code: public void onClick(MenuItemClickEvent event) {
  		FeatureTransaction featureTransaction = mapWidget.getMapModel().getFeatureEditor().getFeatureTransaction();
  		mapWidget.render(featureTransaction, RenderGroup.VECTOR, RenderStatus.DELETE);
  		featureTransaction.undoLastOperation();
  		mapWidget.render(featureTransaction, RenderGroup.VECTOR, RenderStatus.ALL);
  		controller.cleanup();
  	}
docs: Undo the last operation performed on the {@link FeatureTransaction}.
  
  @param event
  The {@link MenuItemClickEvent} from clicking the action.