title: Prevent automatic popToRootViewController on double-tap of UITabBarController
body: <p>The default behavior of a UITabBarController is to pop the contained UINavigationController to the root view controller when a particular tab is tapped a second time. I have a particular use case where I'm wanting this to not work automatically, and I'm having a hard time figuring out how to prevent this.</p>
  
  <p>Has anyone run into this, and if so, what did you do? Do I need to subclass UINavigationController and override popToRootViewController or is there a simpler way?</p>