anchor.diff:  
   type Events = Add
   
  +
  +type ListViewWindow() as x =
  +    inherit Window()
  +    let label = Label()
  +    let button = Button(Content="Add")
  +    let list = ListBox()
  +    do
  +        let sp = StackPanel()
  +        sp.Children.Add label |> ignore
  +        sp.Children.Add list |> ignore
  +        sp.Children.Add button |> ignore
  +        x.Content <- sp
  +    member val Label = label
  +    member val Button = button
  +    member val List = list
  +
   type ItemModel() =
       member val Text = ReactiveProperty("")
   
   type ItemView(elt, m) =
  -    inherit View<Events, FrameworkElement, ItemModel>(elt, m)
  +    inherit View<Events, Label, ItemModel>(elt, m)
        override x.EventStreams = []
  -     override x.SetBindings m = ()
  +     override x.SetBindings m = elt.Content <- m.Text.Value
   type ListModel() =
       member val Items = new ObservableCollection<ItemModel>()
       
   type ListView(elt, m) =
  -    inherit View<Events, Window, ListModel>(elt, m)
  +    inherit View<Events, ListViewWindow, ListModel>(elt, m)
       override x.EventStreams = []
       override x.SetBindings m = ()
   type ListController() =
  
positive.code: open System.Windows
  open FSharp.Qualia
  open System.Collections.ObjectModel
  
  (**
  Collections
  
negative.code: #r "PresentationCore.dll"
  #r "PresentationFramework.dll"
  #r "System.Numerics.dll"
  #r "System.Xaml.dll"
  #r "UIAutomationTypes.dll"
  #r "Rx-Core/lib/net45/System.Reactive.Core.dll"
  #r "Rx-Interfaces/lib/net45/System.Reactive.Interfaces.dll"
  #r "Rx-Linq/lib/net45/System.Reactive.Linq.dll"
  