Ever since I added code to catch replacing of the internal delegate by our C# event implementation (to prevent users from assigning a delegate AND C# events and one not firing, all of the events on NSApplicationDelgate are useless. They will crash on use.
Which is good. Before that, we'd just stop calling your AppDelegate class after you used one.
Should we remove them from XAMCORE_4_0?
From - https://bugzilla.xamarin.com/show_bug.cgi?id=44598