anchor.diff:          body: new ListView.builder(
             itemCount: _items.length,
             itemBuilder: (BuildContext context, int index) => new ListTile(
  +                trailing: new PopupMenuButton(
  +                    onSelected: (_ItemActions action) =>
  +                        _performAction(action, _items[index]),
  +                    itemBuilder: (BuildContext context) =>
  +                        <PopupMenuEntry<_ItemActions>>[
  +                          new PopupMenuItem(
  +                            value: _ItemActions.delete,
  +                            child: new Text('Delete'),
  +                          ),
  +                          new PopupMenuItem(
  +                            value: _ItemActions.edit,
  +                            child: new Text('Edit'),
  +                          ),
  +                        ]),
                   title: new Text(_items[index].value),
                   subtitle: new Text(_items[index].key),
                 ),
           ),
         );
  +
  +  Future<Null> _performAction(_ItemActions action, _SecItem item) async {
  +    switch (action) {
  +      case _ItemActions.delete:
  +        await _storage.delete(key: item.key);
  +        _readAll();
  +
  +        break;
  +      case _ItemActions.edit:
  +        final result = await showDialog<String>(
  +            context: context,
  +            builder: (context) => new _EditItemWidget(item.value));
  +        if (result != null) {
  +          _storage.write(key: item.key, value: result);
  +          _readAll();
  +        }
  +        break;
  +    }
  +  }
  +}
  +
  +class _EditItemWidget extends StatelessWidget {
  +  final TextEditingController _controller;
  +
  +  _EditItemWidget(String text)
  +      : _controller = new TextEditingController(text: text);
  +
  +  @override
  +  Widget build(BuildContext context) {
  +    return new AlertDialog(
  +      title: new Text('Edit item'),
  +      content: new TextField(
  +        controller: _controller,
  +        autofocus: true,
  +      ),
  +      actions: <Widget>[
  +        new FlatButton(
  +            onPressed: () => Navigator.of(context).pop(),
  +            child: new Text('Cancel')),
  +        new FlatButton(
  +            onPressed: () => Navigator.of(context).pop(_controller.text),
  +            child: new Text('Save')),
  +      ],
  +    );
  +  }
   }
   
   class _SecItem {
  
positive.code: }
  
  enum _Actions { deleteAll }
  
  class _ItemsWidgetState extends State<ItemsWidget> {
    final _storage = new FlutterSecureStorage();
  
negative.code: 
    void _addNewItem() async {
      final String key = new Uuid().v4();
      final String value = generateWordPairs().take(2).join(' ');
  
      await _storage.write(key: key, value: value);
      _readAll();
  