title: UICollectionView doesn't call delegate methods
body: <p>I've setup a <code>UICollectionView</code> in a storyboard and connected the dataSource and delegate outlets. I've registered a cell via nib which I dequeue in the <code>cellForItemAtIndexPath:</code> method. </p>
  
  <p>All works perfectly expect that the delegate methods are never called. For example: When touching on a cell, I expect the <code>didSelectItemAtIndexPath:</code> to be called.</p>
  
  <p>I've double-checked the delegate of the collection view - it's assigned correctly.</p>
  
  <p>Does anybody know the reason why the methods are not called?</p>