iPhone: Subviews in UIButtons block the touch, unless...

If you add a UIView or other UIView subclass to a UIButton, the UIView object will block touches/clicks on the UIButton. There's a simple fix to ensure that subviews in your UIButton don't interfere. In the following case, I have a subclass of UIView that loads an image from the web (WebImage), that's created inside a subclass of UIButton:

WebImage *thumb = [[WebImage alloc] initWithFrame:CGRectMake(1, 1, 94, 94) andImageUrl:@"http://mysite.com/thumbnail.png"];
[self addSubview:thumb];
thumb.userInteractionEnabled = NO;
thumb.exclusiveTouch = NO;
[thumb release]; 

All you need to do is set userInteractionEnabled and exclusiveTouch to NO or FALSE, and the subview will no longer block your button.