title: Change UIButton border color on highlight
body: <p>I've got a simple custom UIButton, to which I added:</p>
  
  <pre><code>button.layer.bordercolor = [[UIColor blueColor]CGColor];
  </code></pre>
  
  <p>However, I want to change the .bordercolor when the button is highlighted. I tried adding an action to the button's touchDown action that changes the .bordercolor to red, but when the user lifts their finger, it stays red rather than returning to blue. Any ideas?</p>