Frameworks Engineer, thanks for your answer. I am wondering about this as well. Could you please elaborate on the animation part of your answer? UIBarButtonItem (assuming that's what the calendar app is using) are not views and cannot be animated. Maybe we should animate some certain subview of the navigation bar? That doesn't seem like a good idea either. Or perhaps it is animating on some private view that devs don't have access to? It would be great if you could provide some sample code snippets. Thanks!