title: No ItemSelected call in my UICollectionView?
body: <p>So I'm trying out Xamarin Forms, and I made a control that has a renderer that outputs a UICollectionView. The collection view in question was ported from an Objective C version. In the Objective C version, I implemented <code>collectionView:didSelectItemAtIndexPath:</code> and when I clicked on the item that method was called. But in the Xamarin version, this does not seem to be the case and the <code>ItemSelected</code> method is not called. I've tried using both the <code>Delegate</code> and <code>WeakDelegate</code> versions to no avail. I made sure <code>AllowsSelection</code> is true.</p>
  
  <p>I tried adding a UIButton to the cell, and was able to get a log entry from its TouchUpInside handler, so I don't think it's a matter of another view on top stealing the touches. Pans and such work. And in Simulator I had it highlight the drawn layers and didn't notice anything fishy.</p>
  
  <p>Anyone have any ideas of stuff to try? Thanks.</p>