public void OnInitialize()
        {
            MainScrollView   = CreateScrollView();
            NativeScrollView = (NSScrollView)MainScrollView.NativeObject;

            View.AddSubview(NativeScrollView);


            var windowDelegate = new WindowDelegate();

            windowDelegate.GotFocus += async(s, e) => {
                await windowController.UpdateVersionMenu(DocumentID);
            };
            windowDelegate.LostFocus += (s, e) => {
                windowController.ClearVersionMenu();
            };

            View.Window.WeakDelegate = windowDelegate;


            windowController = (DocumentWindowController)View.Window.WindowController;
            windowController.VersionSelected  += WindowController_VersionSelected;
            windowController.RefreshRequested += WindowController_RefreshRequested;
            windowController.PageChanged      += WindowController_PageChanged;
        }