title: Textfield background-color white, live grey background-color
body: <p>In my storyboard I have a view controller with textfields.
  looks like this:</p>
  
  <p><a href="https://i.stack.imgur.com/QYymP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QYymP.png" alt="enter image description here"></a></p>
  
  <p>white bg-colorif I start my application the textfields bg-color is grey</p>
  
  <p><a href="https://i.stack.imgur.com/nXYOk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nXYOk.png" alt="enter image description here"></a></p>
  
  <p>looks not good</p>
  
  <p>Why? I have no Swift code which sets the bg-color. Any ideas?</p>
  
  <p>(white bg-color)</p>