title: How to detect delete key on an UITextField in iOS 8?
body: <p>I have subclassed UITextField and implemented the UIKeyInput protocol's deleteBackward method to detect backspace being pressed. This works fine on iOS 7 but not on iOS 8.</p>
  
  <p>deleteBackward is not called on the UITextField anymore when I press the backspace key. </p>
  
  <p>I've checked the documentation and the release notes and nothing points to the reason why this  could happen. Any pointers?</p>