ObservableProperty (community toolkit) called ShouldBeVisible in my view model, and this code in my view that reacts to changes to that property:OverlayViewModel.PropertyChanged with OnViewModelPropertyChanged like I do in the view constructor, the overlay takes some 3s to render. Comment out that line and the problem goes away. I've tried wrapping OnViewModelPropertyChanged or the calls to Show() and Hide() with Dispatcher.Invoke(), Dispatcher.InvokeAsync() and Dispatcher.BeginInvoke(), but it changes nothing.