title: Weird frame calculation for UITabBar
body: <p>Sometimes the app shrinks the width of the UITabBar, the 4 icons in the screenshot are usually distributed across the whole width.</p>
  
  <p><a href="https://i.stack.imgur.com/L0O1Z.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/L0O1Z.png" alt="weird uitabbar frame"></a></p>
  
  <p>Is anyone experiencing this and knows why it happens or even better how to fix/avoid it? I think it started happening with Swift, so maybe another of their awesome optimizations?</p>
  
  <p>Also not sure how to reproduce it, happens around twice a week, maybe rotation, segue or app switch.</p>
  
  <p>This screenshot is from an iPhone6 in portrait mode, but happens on other devices too.</p>