title: Placing UIBarButtonItem on storyboard does not appear when run
body: <p>Placing a button on the nav bar of a UIViewController (created by xcode when I added a UITabBarController) looks great on the storyboard, but does not appear when run.</p>
  
  <p>However, adding the button using the following code works fine:</p>
  
  <pre><code>- (void)viewWillAppear:(BOOL)animated {
      [super viewWillAppear:animated];
  
      UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithTitle:@"About"
              style:UIBarButtonSystemItemDone target:nil action:nil];
      self.tabBarController.navigationItem.rightBarButtonItem = rightButton;
  }
  </code></pre>
  
  <p>Thanks in advance.</p>