title: can't click UIButton when it's added to UIImageView
body: <p>guys, i want to click my uiButton after it's added to UIImageVIew, but it doesn't work.
  this is my code :</p>
  
  <pre><code>UIButton *btnDetail = [[UIButton buttonWithType:UIButtonTypeDetailDisclosure]retain];
  
  btnDetail.frame = CGRectMake(0,0,100,100);
  [btnDetail addTarget:self action:@selector(buttonClicked) forControlEvents:UIControlEventAllTouchEvents];
  
  [self.imageView addSubview:btnDetail];
  </code></pre>
  
  <p>the button can't click when i add it to UIImageVIew, but if i don't add  it to UIImageView, it works properly.
  please somebody help me</p>