How to add buttons to navigation controller visible after segueing?
For XCode 6, the UINavigationItem for the 2nd view controller onwards is not added automatically on the View Controller Object inside the storyboard. You will have to drag the UINavigationItem onto the Navigation Bar for that view Controller Object before adding UIBarButtonItem on top of it.
I am not sure why it is designed that way. I only discovered about this a few weeks ago.
If you have a ton of view controllers and very little custom auto-layout stuff in place, you can disable size classes, then re-enable it will add all missing nav bars across your storyboard.
Obviously not recommended if you have a ton of custom auto layout stuff linked up.
If you have just a single UIViewController that's missing a nav bar, just drop a UINavigationItem onto it.
If you're using Xcode 7 beta 4/5, try restarting Xcode it solved the issue for me