iOS Button Click Area Inconsistent - ios

Question

I have a back button in a custom header. Sometimes the click area is the entire button. Sometimes the click area is a small part of the bottom of the button. Any ideas what might cause this? If I use a tap gesture, the gesture recognizer stops firing an event.
Here's what it looks like. The red is the button. The blue is the header container. The green is the header label inside of the content layout.
Initialize my header view. You can see that the button is on the top layer. Everything else gets added to the content view, so any added elements shouldn't interfere with the clickabilitiy.
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
CGFloat statusBarHeight = 0.0;//for iOS below 7.0
if([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0) {
statusBarHeight = [[UIApplication sharedApplication] statusBarFrame].size.height;;
}
self.contentLayout = [[UIView alloc] initWithFrame:CGRectMake(0.0, statusBarHeight, frame.size.width, frame.size.height - statusBarHeight)];
[self addSubview:self.contentLayout];
CGFloat height = 44.0 < self.contentLayout.frame.size.height ? 44.0 : self.contentLayout.frame.size.height;
self.ivBack = [[UIImageView alloc] initWithFrame: CGRectMake(15.0, (height - 15.0) / 2.0, 11.5, 15.0)];
[self.ivBack setImage:[UIImage imageNamed:#"back.png"]];
[self.ivBack setUserInteractionEnabled:YES];
[self.ivBack setHidden:YES];
[self.contentLayout addSubview:self.ivBack];
self.btnBack = [UIButton buttonWithType:UIButtonTypeCustom];
[self.btnBack setAccessibilityLabel:#"btnBack"];
[self.btnBack setFrame: CGRectMake(0.0, 0.0, 50.0, self.frame.size.height)];
[self addSubview:self.btnBack];
self.layer.shadowPath = [UIBezierPath bezierPathWithRect:self.bounds].CGPath;
self.layer.shadowColor = [[UIColor colorWithRed:123.0/255.0 green:123.0/255.0 blue:123.0/255.0 alpha:1.0] CGColor];
self.layer.shadowOffset = CGSizeMake(0, 2.0);
self.layer.shadowRadius = 4.0;
self.layer.shadowOpacity = 0.7;
[self.btnBack setBackgroundColor:[UIColor redColor]];
[self.contentLayout setBackgroundColor:[UIColor blueColor]];
}
return self;
}
Enabling the button and assigning it a click event.
-(void)addBackTarget:(id)target selector:(SEL)selector {
[self.ivBack setHidden:NO];
[self.btnBack addTarget:target action:selector forControlEvents:UIControlEventTouchDown];
}

Answer 1

I have no idea why the above solution was so fickle. The button fit in its container. The container fit in its view. There was nothing in front of the button. To get the back button to work consistently, I made my header a subclass of UINaviationBar. In the subclass I added a UIBarButtonItem to the topItem (I had to initialize this first). Seems to be working great now.