Open Radar

 
Summary:
Under iOS 9, If an application creates a second UIWindow, makes it key and visible, and then later closes the second window by nulling its last reference to it, the application’s first window does not become key; and [application keyWindow] returns nil.

This is a regression from iOS 8 and earlier, where the application’s first window would become key after the second window was closed.

Workaround: If the second window is hidden immediately prior to being closed, the application’s first window does become key as expected.

This issue has been observed (via side effects) on iOS 9 betas 2, 3, and 5, but we did not pin down this cause until beta 5.

Steps to Reproduce:
1. In an iOS application, after launching, observe that [[UIApplication sharedApplication] keyWindow] is the application's first window.
2. Alloc and init a second window. Keep a strong reference to this second window.
3. Make the second window key and visible.
4. Observe that [[UIApplication sharedApplication] keyWindow] returns the second window.
5. Release the strong reference to the second window.
6. Observe that the window disappears from the screen as it is closed.
7. Observe [[UIApplication sharedApplication] keyWindow] now.

Expected Results:
The key window should now be the first window again.

Actual Results:
The key window is nil.

Version:
iOS 9 beta 5.