title: UIView shadow and InterfaceBuilder
body: <p>I want to add a drop shadow using CALayer to a UI(Image)View.
  The following code works generally fine</p>
  
  <pre><code>previewImage.layer.shadowColor = [[UIColor blackColor] CGColor];
  previewImage.layer.shadowOffset = CGSizeMake(1.0f, 1.0f);
  previewImage.layer.shadowOpacity = 1.0f;
  previewImage.layer.shadowRadius = 8.0f;
  </code></pre>
  
  <p>However, this only works if I create that view programmatically and add it as a subview to my main view. When that view is set up in InterfaceBuilder and defined as an IBOutlet UIImageView this does NOT work. No shadow appears.
  So what am I missing here?</p>