title: Add a subview to a UIImageView that is the view outlet of a UIViewController in IB
body: <p>I have a UIViewController object in a .xib file.  I add a UIImageView to it, and then try to add a button as a subview of the UIImageView.  It instead replaces the UIImageView.  It works fine if both are subviews of a UIView.  What gives?  I thought this would work since UIImageView is a subclass of UIView?</p>