title: self.navigationItem.leftBarButtonItem = nil; not working
body: <p>I am busy with an iPad app. I need to hide and show the leftBarButton depending on orientation, after a menu option has been selected and push segue has run.</p>
  
  <p>I am fine with finding the orientation, and my code  <code>self.navigationItem.leftBarButtonItem = nil;</code> is running according to my log, but the button doesn't hide - this only doesn't work after a segue push.</p>
  
  <p>Does anyone know why this isn't happening?</p>