title: iOS13: PopoverPresentationController - the border on the arrow side is missing
body: <p>In the same theme as this post:
  <a href="https://stackoverflow.com/questions/58149863/ios13-uipopoverviewcontroller-showing-uitableviewcontroller-safe-area-problems">ios13 UIPopoverViewController showing UITableViewController - Safe Area problems / Missing parts of table</a></p>
  
  <p>But in my case, it is not especially a UITableViewControllerany any View Controller in a popover on the iPad has the same issue since iOS13.</p>
  
  <p>I have no problem with overlapping content, just the border.</p>
  
  <p><a href="https://i.stack.imgur.com/P0AVK.png" rel="nofollow noreferrer">App screenshot</a></p>
  
  <pre class="lang-swift prettyprint-override"><code>let popoverContent = self.storyboard!.instantiateViewController(withIdentifier: controllerName) as! SelectSceneViewController
  popoverContent.preferredContentSize = CGSize(width: 700,height: 500)
  
  let nav = UINavigationController(rootViewController: popoverContent)
  nav.modalPresentationStyle = UIModalPresentationStyle.popover
  nav.navigationBar.barStyle = navbarStyle
  nav.view.layer.cornerRadius = 10
  nav.view.layer.borderColor = UIColor.white.cgColor
  nav.view.layer.borderWidth = 2
  
  let popover = nav.popoverPresentationController
  popover?.sourceView = button
  popover?.sourceRect = button.bounds
  
  self.present(nav, animated: true, completion: nil)
  </code></pre>