This looks like just a simple problem, but I can't find what's wrong.
I have a UINavigationController pointing to a UIViewController A, pointing to a UITabBarController. The UITabBarController handles two UIViewControllers B & C, so I can see two tab bar item on the UITabBarController.
When the app run, the UIViewController A is shown. Then after tapping on a button, the UIViewController B is shown (which is supposedly within the UITabBarController). But the tab bar is not shown. Only the UIViewController B and navigation bar.
Can someone help why this is happening?
EDIT: some screenshots:

