title: In iOS6, UIViewController's view position is wrong at app launch
body: <p>IEverything works fine before iOS 6. I have a <code>UIViewController</code> subclass in a <code>UINavigationController</code> as usual. Its view is shrinking down about 20 px as if there is another status bar up top. When I push and pop the view back. The view went back to its correct position. I found out it's because <code>UIViewControllerWrapperView</code> (got by using <code>self.view.superview</code>) frame got wrong somehow in iOS 6.</p>
  
  <p>Doing NSLog in <code>viewDidAppear</code></p>
  
  <p>At app launch ...</p>
  
  <pre><code>self.view.frame: {{0, 0}, {768, 891}} // was {{0, 0}, {768, 911}} in iOS5.1
  self.view.superview: &lt;UIViewControllerWrapperView: 0x9dddb80; frame = (0 20; 768 891); autoresize = W+H; layer = &lt;CALayer: 0x9dddc30&gt;&gt; 
  // was (0 0; 768 911); in iOS5.1
  </code></pre>
  
  <p>After push and pop view controller (correct value) ...</p>
  
  <pre><code>self.view.frame: {{0, 0}, {768, 911}}
  self.view.superview: &lt;UIViewControllerWrapperView: 0x9dddb80; frame = (0 0; 768 911); autoresize = W+H; layer = &lt;CALayer: 0x9dddc30&gt;&gt;
  </code></pre>
  
  <p>It never happens before. How does this appear in iOS 6 ?</p>