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: 
      samplesMenu.listen('MDCMenu:selected', (e) {
        var index = (e as CustomEvent).detail['index'];
        var gistId = samples.elementAt(index).gistId;
        router.go('gist', {'gist': gistId});
      });
    }
  