[Menge]

Now I am even more confused. What is Apple's license on Apple's UI elements that facebook can make this derivative work?

From reading the description it sounded like they were making original elements in the style of Apple's for apps with non-native features that need to blend in.

[delinka]

I'm sure the license that allows me, a 3rd party app developer, to make 'derivative works' (native applications) that use Apple's UI elements, also permits this kind of use. However, I am currently disinclined to read the current developer license agreement to find out if this actually is the case.