title: UIPopoverController Nav Bar Appearance
body: <p>I am using this code to customise my nav bar image throughout my app.</p>
  
  <pre><code>UIImage *navBarTexture = [[UIImage imageNamed:@"NavBarTexture_iPad"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];
      [[UINavigationBar appearance] setBackgroundImage:navBarTexture forBarMetrics:UIBarMetricsDefault];
      [[UINavigationBar appearance] setBackgroundImage:navBarTexture forBarMetrics:UIBarMetricsLandscapePhone];
  </code></pre>
  
  <p>This works wonders. However, when using this image on the nav bar in UIPopoverControllers, it looks a bit strange. The default Apple image for it is what I want to use, how can I make it retain that original appearance?</p>
  
  <p>I know I can use <code>appearanceWhenContainedIn:</code> however if I return nil as an image, I just get a black space. </p>