title: iOS9 supportedInterfaceOrientationsForWindow stops getting called
body: <p>I want to show 1 or 2 UIViewcontrollers in Landscape mode while others in Portrait.
  For this purpose I have implemented this function in AppDelegate.</p>
  
  <pre><code>-(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window
  {
      return self.orientation;
  }
  </code></pre>
  
  <p>where in AppDelegate.h, orientation is:</p>
  
  <pre><code>@property (nonatomic, assign) UIInterfaceOrientationMask orientation;
  </code></pre>
  
  <p>In UIViewcontroller(s) where I need Landscape orientation. I place this code </p>
  
  <pre><code>-(void)viewWillAppear:(BOOL)animated
  {
      self.appDelegate.orientation = UIInterfaceOrientationMaskLandscape;
  }
  </code></pre>
  
  <p>and</p>
  
  <pre><code>-(void)viewWillDisappear:(BOOL)animated
  {
      self.appDelegate.orientation = UIInterfaceOrientationMaskPortrait;
  }
  </code></pre>
  
  <p>However, when I go to 'LandscapeViewController' it works ok, I go back, it works ok, I again go to 'LandscapeViewController' its ok, and then when I comes back, supportedInterfaceOrientationsForWindow method stop getting called. Any reason for that? or I am doing something weird?</p>