anchor.diff:  
       _touchCallback?.call(response);
     }
  +
  +  @override
  +  void attach(PipelineOwner owner) {
  +    super.attach(owner);
  +    _validForMouseTracker = true;
  +  }
  +
  +  @override
  +  void detach() {
  +    _validForMouseTracker = false;
  +    super.detach();
  +  }
   }
  
positive.code: 
    RadarTouchedSpot? _lastTouchedSpot;
  
    @override
    void performLayout() {
      size = computeDryLayout(constraints);
  
negative.code: import 'package:flutter/foundation.dart';
  import 'package:flutter/gestures.dart';
  import 'package:flutter/rendering.dart';
  import 'package:flutter/services.dart';
  
  import 'radar_chart_painter.dart';
  
  