public LibraryToolTipPopup() { this.Placement = PlacementMode.Custom; this.AllowsTransparency = true; this.CustomPopupPlacementCallback = PlacementCallback; this.DataContext = null; this.Child = tooltip; this.Loaded += LoadMainDynamoWindow; toolTipTimer = new LibraryToolTipTimer(); toolTipTimer.TimerElapsed += (dataContext) => { OpenCloseLibraryToolTipPopup(dataContext); }; }