In iOS 7, navigator bar covers top of the interface


On page 267, we create a detailViewController with the following line:

When I updated to Xcode 5, the navigator bar now covers the top of the DetailViewController instead of the top of the DetailViewController starting below the navigator bar. Strangely, when I comment out the above line of code, it does NOT crash, AND the navigator bar does NOT cover the top of the DetailViewController.

Can anyone have some insight into these behaviors, and the way views should be presented in iOS 7?