I have implemented a UIViewController subclass where I display a UIView using a storyboard. The view is embedded in a UITabViewController. I have copied the demo and removed the parts that seem to be just for a demo (existing messages).
Currently there are UI issues with the keyboard (no display) and the "New Message" input field. I wonder if perhaps they are behind the tab view controller, or if there's something I am missing.
I stupidly failed to properly configure the view controller so an empty view controller without any code behind it was showing.