anchor.diff:        api.rootUrl = serverUrl;
         window.localStorage['null_safety'] = 'false';
       }
  +
  +    updateVersion();
   
       QueryParams.nullSafety = enabled;
   
  
positive.code: 
    void _handleNullSafetySwitched(bool enabled) {
      var api = deps[DartservicesApi] as DartservicesApi;
      if (enabled) {
        api.rootUrl = nullSafetyServerUrl;
        window.localStorage['null_safety'] = 'true';
  
negative.code: 
      docHandler = DocHandler(editor, _context);
  
      updateVersion();
  
      analysisResultsController = AnalysisResultsController(
          DElement(querySelector('#issues')),
  