title: UIPopoverController should prevent scrolling via status bar
body: <p>I've found that when presenting a UIPopoverController not all controls in the presenting view are disabled. Specifically, the navbar buttons (e.g. 'back') remain selectable. This is a defect in my opinion - it allows the popover to remain on screen, while the view stack pops behind it.</p>
  
  <p>Oh well, at least this can be rectified using <code>self.aboutPopoverController.passthroughViews = nil</code> immediately after presentation.</p>
  
  <p>Except this doesn't disable the status bar, which is often set up to scroll the view's content to the top.</p>
  
  <p>The end result is the ability to present a popover, and then (in the background) scroll the view so that the small arrow/tab on the popover is no longer aligned with the original touch point.</p>
  
  <p>Can anyone shed some light on this behavior? Is it a feature or a bug? Any workarounds?</p>