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