UITabbarController in Xcode 8 shows a blue rectangle inside a storyboard view : <p>How can I fix this ? I can't see anything at all.</p>

<p><a href="https://i.stack.imgur.com/TPmmU.png" rel="noreferrer"><img src="https://i.stack.imgur.com/TPmmU.png" alt="enter image description here"></a></p>
