title: Unable to set custom class for UICollectionView in Storyboard
body: <p>I'm unable to set the custom class attribute in Storyboard mode for a UICollectionView. Below you can see the screenshot of where I'm entering this. Generally when I extend a view controller it will autocomplete the custom class name, but in this case it doesn't, and if I click away to a different UI element and click back to the CollectionView then the custom class is empty again (shows the UICollectionView placeholder).</p>
  
  <p><a href="https://i.stack.imgur.com/WwS3o.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WwS3o.png" alt="Custom Class attribute"></a></p>
  
  <p>Here is the MyMediaCollectionController.m</p>
  
  <pre><code>#import "MyMediaCollectionController.h"
  @interface MyMediaCollectionController ()
  @end
  
  @implementation MyMediaCollectionController
      static NSString * const reuseIdentifier = @"Cell";
  
      - (void)viewDidLoad {
           [super viewDidLoad];
           [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:reuseIdentifier];
      }
  @end
  </code></pre>
  
  <p>and MyMediaCollectionController.h:</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  
  @interface MyMediaCollectionController : UICollectionViewController
  @end
  </code></pre>
  
  <p>Thanks in advance!</p>