anchor.diff:                  checked: _dismissDirection == DismissDirection.startToEnd,
                   child: const Text('Only swipe right'),
                 ),
  +              CheckedPopupMenuItem<LeaveBehindDemoAction>(
  +                value: LeaveBehindDemoAction.confirmDismiss,
  +                checked: _confirmDismiss,
  +                child: const Text('Confirm dismiss'),
  +              ),
               ],
             ),
           ],
  
positive.code:       ),
      );
    }
  }
  
negative.code: class LeaveBehindDemoState extends State<LeaveBehindDemo> {
    static final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
    DismissDirection _dismissDirection = DismissDirection.horizontal;
    bool _confirmDismiss = true;
    List<LeaveBehindItem> leaveBehindItems;
  
    void initListItems() {
  