I think I've found the cause: Document Info window in IB has a warning: "'Selected Navigation Controller (Second)' has nib name property set to 'SecondView.nib', but this view controller is not intended to have its view set in this manner."

Bummer.

I've built nib in Interface Builder that has UITabBarController at top level and switches between UINavigationControllers.

It works fine when everything is in a single nib file, but I'd like to use separate nib files for UINavigationControllers.

Starting with Apple's TabBar template, if I just change class of SecondView to UINavigationController, it all breaks:

and all I get is this:

Is it possible to have separate file for UINavigationController without programmatically setting everything?

I would like TabBarController to handle loading and unloading of nibs.