title: presentViewController:animated:completion wont Animate
body: <p>this is my first question so please go easy!!</p>
  
  <p>I have an iOS app that has 5 tab bars, each of which contains a Navigation controller. It seems that no matter where I call presentViewController:animated:completion from, I get no animation from the transition, the presented view controller just appears on screen!</p>
  
  <p>This is also happening with my UIImagePickerController that I am presenting from one of my tabs. No presenting animation, but when i dismiss it it DOES animate away!</p>
  
  <p>Here is a sample of the code, sent from a code generated tab bar button, with its action hooked up to a method which simply does this..</p>
  
  <pre><code>UserRegistrationViewController *userRegistration = [[UserRegistrationViewController alloc] init];
  
  userRegistration.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
  
  [self presentViewController:userRegistration animated:YES completion:nil];
  </code></pre>
  
  <p>If anyone has ANY ideas of things that I could try I would be most grateful!</p>