anchor.diff:        |> Stream.subscribeJob (fun _ ->
            Stream.MVar.updateFun modelMVar << Map.filter <| fun _ -> isActive)
   
  -      // This updates the CompleteAll check box for marking all ToDo items as
  +      // This updates the CompleteAll checkbox for marking all ToDo items as
         // completed or active.
         Stream.MVar.tap modelMVar
         |> Stream.mapFun (fun model ->
  
positive.code: module Id =
    let mutable private id = 0L
  
    /// Returns a new unique id.
    let next () = Interlocked.Increment &id
  
  [<STAThread; EntryPoint>]
  
negative.code: // some builtin WPF controls and overuses choice streams to show some more
  // choice stream usage patterns.  WPF is a fundamentally imperative GUI
  // framework and this example does not try to rewrite WPF as a more declarative
  // framework.  Some of the simple techniques used in this example, such as using
  // an immutable map as the model and removing and adding all controls to a panel
  // when the model changes, do not necessarily scale.  Would have used XAML type
  // provider, but it currently does not mix with PCL.
  //
  