anchor.diff:                  treeCol.SetCellDataFunc(padTreeView.TextRenderer, new TreeCellDataFunc(setCellText))
   
                   padTreeView.AppendColumn treeCol |> ignore
  -                padTreeView.Realized.Add(fun _ -> refillTree |> ignore)
  +                padTreeView.Realized.Add(fun _ -> treeViewRealized <- true; refillTree |> ignore)
                   padTreeView.Selection.Changed.Subscribe(fun _ -> jumpToDeclaration false) |> ignore
                   padTreeView.RowActivated.Subscribe(fun _ -> jumpToDeclaration true) |> ignore
   
  
positive.code:     inherit TextEditorExtension()
      let mutable treeView : PadTreeView option = None
      let mutable refreshingOutline : bool = false
  
      let refillTree =
          match treeView with
          | Some(treeView) ->
              if treeView.IsRealized then
                  let ast = maybe { let! context = x.DocumentContext |> Option.ofNull
                                    let! parsedDocument = context.ParsedDocument |> Option.ofNull
                                    let! ast = parsedDocument.Ast |> Option.tryCast<ParseAndCheckResults>
  
negative.code:     let updateDocumentOutline _ =
        if not refreshingOutline then
          refreshingOutline <- true
          GLib.Timeout.Add (1000u, (fun _ -> refillTree())) |> ignore
  
      override x.Initialize() =
          base.Initialize()
  