title: UIPopover locking background view
body: <p>I am trying to replicate the iPad passcode view.  Which basically is a popover with no arrow direction, that locks the background view kinda like a modal view controller. </p>
  
  <p>My question: Is there a way to lock the underlying background view when presenting a popover.</p>
  
  <p>My idea:  The only real solution that i could come up with is placing that popover inside a modal view controller.  and presenting it that way.</p>
  
  <p>Thoughts?</p>