1. Create a brand-new project using the "Master Detail" template
2. Edit the detail controller to add something - anything - to the navigationItem, e.g. a segmented control or a label to navigationItem.titleView. Or add buttons. Doesn't matter.
3. Run the project on an iPad
4. Bring in another app using the multitasking gestures; dock the app on the side (left or right).
5. Slide the divider to change the size of the two apps. Make the UISVC collapse; then make it expand.
6. Notice when expanding, the navigationItem from the Detail controller is gone. Poof!
The expection is that the navigation bar and its items remains constant.