title: shouldChangeCharactersInRange is not called for keyboard suggestions
body: <p>I have a keyboard and I pick suggestions of Chinese characters from it but it doesn't call shouldChangeCharactersInRange method on tapping suggestions. It is only called if user types in text field.</p>
  
  <p>I have searched for this question and seems like no one has given any proper answer for this one.</p>
  
  <p>I found following workaround that resolves my issue.</p>
  
  <p><strong>EDITED:</strong></p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(textChanged:)
                                               name:UITextFieldTextDidChangeNotification
                                             object:textField];
  
  
  - (void)textChanged:(NSNotification*)notification
    {
       [self textField:textField shouldChangeCharactersInRange:NSMakeRange(0, self.stringXYZ.length) replacementString:self.stringXYZ.text];
    }
  </code></pre>