title: Popping viewcontroller and then back to RootViewController doesn't seem to work
body: <p>I have an app that pushes four viewcontrollers on the stack.  In the fourth view controller, I do a PopViewController, so I should be back at the 3rd viewcontroller, and in the viewWillAppear method, I do a PopToRootViewController.  This does not get me back to the first viewcontroller correctly.  The code is straightforward, just a </p>
  
  <pre><code>[self.navigationController pushViewController:nextController animated:YES]
  </code></pre>
  
  <p>in each of the first 3 viewcontrollers, and in the fourth</p>
  
  <pre><code>[self.navigationController popViewControllerAnimated:YES].  
  </code></pre>
  
  <p>In the 3rd viewcontroller, I have a viewWillAppear method which does:</p>
  
  <pre><code>[self.navigationController popToRootViewControllerAnimated:YES].
  </code></pre>
  
  <hr>
  
  <p>As I go through the views, I get the following:</p>
  
  <p>Start app:   </p>
  
  <pre><code>         Back:               Title: FirstLevel
  </code></pre>
  
  <p>Press OK:    </p>
  
  <pre><code>         Back: FirstLevel    Title: SecondLevel
  </code></pre>
  
  <p>Press OK:    </p>
  
  <pre><code>         Back: SecondLevel   Title: ThirdLevel
  </code></pre>
  
  <p>Press OK:</p>
  
  <pre><code>         Back: ThirdLevel    Title: FourthLevel
  </code></pre>
  
  <p>Press OK: which pops back 1 and then pops back to root:</p>
  
  <pre><code>         Back: FirstLevel    Title: ThirdLevel
  </code></pre>
  
  <p>If I press OK now:</p>
  
  <pre><code>         Back: ThirdLevel    Title: SecondLevel
  </code></pre>
  
  <p>I'm sorry if this is confusing.  Should I be able to pop back one view controller and then immediately pop back to the root?</p>
  
  <p>Thanks for any help.</p>