title: Swift bringSubViewToFront not working
body: <p>I have a number of labels and buttons on the screen. To act on user tapping anywhere on the screen, I have created a UIButton ("wholeScreenButton"), made its background clear and made it the same size as superview. Now at runtime I am using below code to bring the button on top of every other label. </p>
  
  <pre><code>self.wholeScreenButton.bringSubviewToFront(self.wholeScreenButton)
  </code></pre>
  
  <p>But it is not working. User can still tap on some of the buttons which are supposed to be underneath the wholeScreenButton and supposed to be unreachable.
  What am I doing wrong?</p>