code: public boolean execute(Canvas target, Menu menu, MenuItem item) {
  		FeatureTransaction featureTransaction = mapWidget.getMapModel().getFeatureEditor().getFeatureTransaction();
  		if (featureTransaction != null) {
  			MenuContext graphics = mapWidget.getMenuContext();
  			String targetId = graphics.getRightButtonName();
  			if (targetId != null && TransactionGeomIndexUtil.isVertex(targetId)) {
  				index = TransactionGeomIndexUtil.getIndex(targetId);
  				return true;
  			}
  		}
  		return false;
  	}
docs: Implementation of the <code>MenuItemIfFunction</code> interface. This will determine if the menu action should be
  enabled or not. In essence, this action will be enabled when the context menu event occurred on a vertex of the
  painted <code>FeatureTransaction</code>.