anchor.diff:                                  let currentSnapshot = doc.TextBuffer.CurrentSnapshot
                                   let span = SnapshotSpan(currentSnapshot, 0, currentSnapshot.Length)
                                   classificationChanged.Trigger(self, ClassificationChangedEventArgs(span))
  -                        finally 
  -                            isWorking <- false
  -                    } |> Async.StartInThreadPoolSafe
  -                | None -> ()
  +                        with e -> Logging.logException e
  +                    } 
  +                Async.Start (worker, cancelToken.Token) 
  +            | None -> ()
   
       let dte = serviceProvider.GetService<EnvDTE.DTE, SDTE>()
       let events = dte.Events :?> EnvDTE80.Events2 
  
positive.code: 
  open System
  open System.IO
  open System.ComponentModel.Composition
  open Microsoft.VisualStudio.Text
  open Microsoft.VisualStudio.Text.Editor
  
negative.code:             return! projectFactory.CreateForFileInProject doc.TextBuffer doc.FilePath projectItem.ContainingProject }
  
      let updateSyntaxConstructClassifiers force =
          let cancelToken = new CancellationTokenSource() 
          cancellationToken.Swap (fun _ -> Some (cancelToken))
          |> Option.iter (fun oldToken -> 
              oldToken.Cancel()
              oldToken.Dispose())
  
          let snapshot = doc.TextBuffer.CurrentSnapshot
          let currentState = state.Value
          let needUpdate =
              match force, currentState with
              | true, _ -> true
              | _, None -> true
              | _, Some state -> state.SnapshotSpan.Snapshot <> snapshot
                   
          if needUpdate then
              match getProject() with
              | Some project ->
                  debug "[SyntaxConstructClassifier] - Effective update"
                  let worker = 
                      async {
                          try
                              let! allSymbolsUses, lexer =
                                  vsLanguageService.GetAllUsesOfAllSymbolsInFile (snapshot, doc.FilePath, project, AllowStaleResults.No)
                              let! parseResults = vsLanguageService.ParseFileInProject(doc.FilePath, snapshot.GetText(), project)
  
                              let spans = 
  