anchor.diff:      title: Text(widget.title),
     ),
     body: Center(
  -    floatingActionButton: FloatingActionButton(
  -      onPressed: _incrementCounter,
  -      tooltip: 'Increment',
  -      child: Icon(Icons.add),
  -    ),
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
  
positive.code:          ),
        ],
      ),
    ),
  );
  ```
  
negative.code:       ],
        mainAxisAlignment: MainAxisAlignment.center,
      ),
    ),
    floatingActionButton: FloatingActionButton(
      child: Icon(Icons.add),
      onPressed: _incrementCounter,
      tooltip: 'Increment',
    ),
  );
  ```
  