title: UITabbarController selectedIndex and selectedViewController do not work
body: <p>I've tried to put following two lines into <code>- (void)viewDidLoad.</code></p>
  
  <pre><code>self.tabBarController.selectedIndex = 3;
  self.tabBarController.selectedViewController = [self.tabBarController.viewControllers objectAtIndex:3];
  </code></pre>
  
  <p>At that time, only Tabbar index to change 3 but View Controller remained at default view controller, mean 0. Is there any thing missing in my coding?</p>