anchor.diff:  library new_playground;
   
   import 'dart:async';
  -import 'dart:collection';
   import 'dart:html' hide Console;
   
   import 'package:dart_pad/editing/editor_codemirror.dart';
  
positive.code:     });
    }
  }
  
negative.code:     var element = querySelector('#samples-menu');
  
      // Use SplayTreeMap to keep the order of the keys
      var samples = [
        Sample('215ba63265350c02dfbd586dfd30b8c3', 'Hello World'),
        Sample('e93b969fed77325db0b848a85f1cf78e', 'Int to Double'),
        Sample('b60dc2fc7ea49acecb1fd2b57bf9be57', 'Mixins'),
        Sample('7d78af42d7b0aedfd92f00899f93561b', 'Fibonacci'),
        Sample('a559420eed617dab7a196b5ea0b64fba', 'Sunflower'),
        Sample('cb9b199b1085873de191e32a1dd5ca4f', 'WebSockets'),
        Sample('67acac89cb32605b61dea6f26adb5dc9', 'Flutter Hello World'),
        Sample('9e574ab997b3217fcef3f600d0c6954c', 'Flutter Todo App'),
        Sample('b70710dde62f636bccfec5a1cfaa6bc4', 'Flutter Sliding Square'),
      ];
  
      var listElement = UListElement()
        ..classes.add('mdc-list')
  