Open Radar

 
Summary:
If there is an additional UIWindow allocated - it even hasn't to be active or been the keyWindow at any time, the root-view of the topViewController of a UINavigationController gets the wrong frame assigned after the push / pop happend and the iPad gets rotated at the same time. 
The timing of the rotation is important and it may take some time to achieve it - but after some exercise, we reproduced it in 5 of 6 cases.

This is not a made up example - we observed it in our app and spent hours of finding out that an additional UIWindow causes this issue. It is a show-stopper for us to use UIWindows any longer in our app. Although it only happens relatively rarely, when the number of active users is high enough, any "relatively rarely" will become "to often".

Steps to Reproduce:
1. Open the attached project
2. Execute it on an iPad 2 simulator
3. Click the "Push"-button
4. Rotate the simulator while the push is performed
5. The frame of the view should be wrong

If you struggle to reproduce it, i also attached a video inside the zip. It can also reproduced on a device - i recommend to remove the comments for the dispatch_after-block in ViewController.m so that the push happens after 0.3 seconds, that makes it easier to achieve (tried on an iPad Air 1gen).

Expected Results:
The pure existance of an additional UIWindow should never ever change the layout of views and viewcontrollers that belong to an other UIWindow, but this is currently the case.

Actual Results:
I should be able to allocate as many UIWindows as I want to, and it should not change the behaviour of the app whatsoever.

Version:
iOS 9.2.1

Notes:


Configuration:
iPad 2 Simulator, iPad Air

Attachments:
'AnimationTransitionWithRotationBug.zip' was successfully uploaded.