title: UIButton UIControlEventTouchUpInside does not fire, but UIControlEventTouchDown does fire
body: <p>I am implementing <code>UIButton</code> and my <code>UIControlEventTouchUpInside</code> event does not fire, even though <code>UIControlEventTouchDown</code> does fire.</p>
  
  <pre><code>UIButton *btnClose = [UIButton buttonWithType:UIButtonTypeCustom];
  NSString *filePathImage = @"img.png";
  NSString *filePathImageTap = @"img-tap.png";
  UIImage *buttonImage = [UIImage imageWithContentsOfFile:filePathImage];
  UIImage *buttonImageTap = [UIImage imageWithContentsOfFile:filePathImageTap];
  [btnClose setImage:buttonImage forState:UIControlStateNormal];
  [btnClose setImage:buttonImageTap forState:UIControlStateSelected];
  [btnClose setImage:buttonImageTap forState:UIControlStateHighlighted];      
  [btnClose addTarget:self action:@selector(close:) forControlEvents:UIControlEventTouchUpInside];    
  [self.view addSubview:btnClose];
  </code></pre>