title: Size Class for regular width / any height not applied at runtime on iPad
body: <p>I am using size classes in a xib for UITableViewHeaderFooterView. I have installed: a default constant, one for compact width any height, and one for regular width any height. The content shows up correctly in Xcode IB previews, but the regular width size class doesn't seem to be applied at all in the iPad simulator or actual iPad.</p>
  
  <p>Size classes were off in the storyboard that contains the main UITableViewController, but turning them on didn't help.</p>
  
  <p>Thoughts? </p>
  
  <p>p.s. It might even help to know how to tell what size class is actually being used at runtime in debug mode... anyone know how to do that? </p>