title: UIButton touch up inside event not working in ios5 while it's ok in ios6
body: <p>I had a project which contains lots of UIButton, using xcode 4.5 and storyboard and ARC. after testing in ios6, everything goes fine. But in ios5, UIButton touch up inside event not working, the action not called. I tried to use touch down and it works. However, I have a lot of UIButton, I cannot change that one by one. what's more, the touch down event does give a good experience.</p>
  
  <p>I used code below in many of my view controllers:
  in viewDidLoad:</p>
  
  <pre><code>UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                                        action:@selector(dismissKeyboard)];
  
  [self.view addGestureRecognizer:tap];
  
  -(void)dismissKeyboard {
         [aTextField resignFirstResponder];
  }
  </code></pre>
  
  <p>this might be the reason. I will check it out later. But it works in ios6.
  Do you know what's wrong ? Thanks very much!</p>