title: UITextField with rounded corners - setting layer in run time attributes in IB don't work
body: <p>I am trying to create a rounded corners UITextField by modifying the runtime attributes in Interface Builder.</p>
  <p>Here is what I want it to look like:</p>
  <p><img src="https://i.stack.imgur.com/T0yRg.png" alt="rounded corners text field" /></p>
  <p>Here is what I'm doing:</p>
  <p><img src="https://i.stack.imgur.com/Lq6qO.png" alt="runtime attribute modification" /></p>
  <p>and here is the undesired result:</p>
  <p><img src="https://i.stack.imgur.com/lKJNk.png" alt="enter image description here" /></p>
  <p>Any idea of what I am doing wrong?</p>