title: UITextField delegate jumping to 100% CPU usage and crashing upon using keyboard shortcut
body: <p>So, I have a <code>UITextField</code> subclass which is it's own <code>Delegate</code> and is crashing when keyboard shortcuts are used. It maxes out on <code>CPU</code> and doesn't give an error. Without assigning itself as it's <code>Delegate</code>, it works without problem. When it is assigned as it's <code>Delegate</code>, it crashes even when using none of the (optional) methods.</p>
  
  <p>Try it yourself:</p>
  
  <p>Subclass <code>UITextField</code>.</p>
  
  <pre><code>- (id)initWithFrame:(CGRect)frame
  {
      self = [super initWithFrame:frame];
      if (self) {
  
          self.delegate = self;
  
      }
      return self;
  }
  </code></pre>
  
  <p>It should crash.</p>
  
  <p><strong>EDIT</strong>
  Backtrace:</p>
  
  <pre><code>* thread #1: tid = 0x3bb8d, 0x39f14726 libobjc.A.dylib`lookUpImpOrNil + 18, queue = 'com.apple.main-thread, stop reason = signal SIGSTOP
      frame #0: 0x39f14726 libobjc.A.dylib`lookUpImpOrNil + 18
      frame #1: 0x39f0dcb6 libobjc.A.dylib`class_respondsToSelector + 34
      frame #2: 0x39f1d05c libobjc.A.dylib`-[NSObject respondsToSelector:] + 32
      frame #3: 0x323b9242 UIKit`-[UITextField respondsToSelector:] + 46
      frame #4: 0x325c88a2 UIKit`-[UITextField customOverlayContainer] + 50
      frame #5: 0x325c8730 UIKit`-[UITextField automaticallySelectedOverlay] + 28
      frame #6: 0x32554208 UIKit`-[UIKeyboardImpl inputOverlayContainer] + 424
      frame #7: 0x32553942 UIKit`-[UIKeyboardImpl _autocorrectPromptRects] + 454
      frame #8: 0x323c7530 UIKit`-[UIKeyboardImpl updateAutocorrectPrompt:] + 368
      frame #9: 0x323e63e0 UIKit`-[UIDelayedAction timerFired:] + 80
      frame #10: 0x305fbe6c Foundation`__NSFireTimer + 64
      frame #11: 0x2fbe1e86 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 14
      frame #12: 0x2fbe1aa2 CoreFoundation`__CFRunLoopDoTimer + 794
      frame #13: 0x2fbdfe2a CoreFoundation`__CFRunLoopRun + 1218
      frame #14: 0x2fb4a540 CoreFoundation`CFRunLoopRunSpecific + 524
      frame #15: 0x2fb4a322 CoreFoundation`CFRunLoopRunInMode + 106
      frame #16: 0x348812ea GraphicsServices`GSEventRunModal + 138
      frame #17: 0x324011e4 UIKit`UIApplicationMain + 1136
      frame #18: 0x0009929c Today`main(argc=1, argv=0x27d79c80) + 164 at main.m:29
  </code></pre>