anchor.diff:        e.text = description == null ? '' : description;
       }
     }
  -
  +  
  +  void _setBackup () {
  +    _lastRun = new Map();
  +    _lastRun['dart'] = context.dartSource;
  +    _lastRun['html'] = context.htmlSource;
  +    _lastRun['css'] = context.cssSource;
  +  }
  +  
     void _setGistId(String id) {
       if (id == null || id.isEmpty) {
         _gistId = null;
  
positive.code:     context.dartSource = sample.dartCode;
      context.htmlSource = sample.htmlCode;
      context.cssSource = sample.cssCode;
    }
  
    void showGist(RouteEnterEvent event) {
  
negative.code:     }
  
      _showGist(gistId, run: page == 'run');
      _backupRun();
    }
  
    void registerMessageToast() {
  