title: didSelectItem not called on UICollectionView
body: <p><strong>UPDATE</strong></p>
  
  <p>If I tap and drag on my UICollectionViewCell, then release, didSelectItem gets called. But if I just tap, it doesn't recognise the tap! Why is that?</p>
  
  <p>I have a UIViewController with three container views (embedded via the Storyboard). When I press a button, one of these views appears. Each container view is managed by a <code>UIViewController</code> that contains a <code>UICollectionView</code>. I control this <code>UICollectionView</code> using <a href="https://github.com/Instagram/IGListKit" rel="nofollow noreferrer">IGListKit</a>. Each cell is managed by something called a section controller - a piece of code that handles the delegate and datasource methods for each cell in the section, e.g. <code>cellForItem</code>, <code>didSelectItem</code>... However, when I select a cell, <code>didSelectItem</code> is never called. I've checked the obvious things like making sure data sources are connected and making sure the collection view/cell has userInteraction enabled. What's strange is this same setup works in another part of my app (using the same section controller), except the collection view there isn't embedded in a container view. Anyone have any idea what might be happening?</p>
  
  <p>Some code:</p>
  
  <p>Assigning my container view to a variable:</p>
  
  <pre><code>override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
      if segue.identifier == "ViewersOfLivestreamViewController" {
          if let viewController = segue.destination as? LivestreamInvitationParentViewController {
              viewersOfLivestreamViewController = viewController
              viewersOfLivestreamViewController.delegate = self
          }
      }
  }
  </code></pre>
  
  <p>Initialising an adapter inside my container view to handle the <code>UICollectionView</code>:</p>
  
  <pre><code>adapter = ListAdapter(updater: ListAdapterUpdater(), viewController: self, workingRangeSize: 10)
  adapter.collectionView = collectionView
  adapter.dataSource = self
  adapter.scrollViewDelegate = self
  </code></pre>
  
  <p>Setting the section controller that the cells use:</p>
  
  <pre><code>func listAdapter(_ listAdapter: ListAdapter, sectionControllerFor object: Any) -&gt; ListSectionController {
      let sectionController = FriendsSectionController()
      sectionController.sectionModel = model
      sectionController.delegate = self
      return sectionController
  }
  </code></pre>
  
  <p>Inside my section controller, this function should get called, but never does:</p>
  
  <pre><code>override func didSelectItem(at index: Int) {
      // This never gets called
  }
  </code></pre>