UIWindow's root view controller does not rotate to landscape at app launch

Question

I am developing a xib-based landscape-only app. The app launches in landscape correctly. However, the view in my main ViewController is presented in portrait. That is, it is

Answer 1

In iOS 8, settings windows frame to the UIScreen is also necessary, as it won't get automatically updated.

self.window.frame = [UIScreen mainScreen].bounds;