Open Radar

 
Summary:
After following a specific set of steps (described below), the top UINavigationBar associated with the main UINavigationController for Messages (MobileSMS.app) remains hidden on the conversation view where it should be shown.

Steps to Reproduce:
1. Open Messages and navigate to a conversation thread that contains pictures sent or received via MMS.
2. Tap one of the sent or received pictures to open the picture viewer for that conversation.
3. Let the phone go to sleep or press the power button to put it to sleep.
4. Have another person (possibly the same person as you were viewing the conversation thread of) send you an MMS.
5. Slide the "Slide to View" slider when the message is received.

Expected Results:
The conversation thread is shown so the new message can be viewed, with the typical navigation toolbar in place.

Actual Results:
The conversation thread is shown after a push animation (rather than a pop) from the previous picture viewer, and the navigation toolbar remains hidden.

Notes:
• This bug may also occur when receiving a generic SMS rather than an MMS, but I haven't tested that case.
• Perhaps the picture viewer view class simply needs a "-viewWillDisappear:" implementation to show the navigation toolbar again? Seems the most likely fix for the bug. The bug most likely was the engineer taking a shortcut by assuming that the view will never be popped unless that toolbar is already shown, which clearly isn't the case for certain edge cases.