Edit

After further testing, it appears that the part of my button that are not clickable are where the status bar used to be. I'm hiding the status bar with :

// -- Override point for customization after app launch    
[[UIApplication sharedApplication] setStatusBarHidden:YES];

But it's still receiving touches. Any idea on how to disable this?

Is there's a bounding box on an application that receives touch events? I created a few sample round rect buttons and placed them in different places in my view. The ones in the center of the view receive touch events (and show the highlighted blue color) but if I place a button near the edges of the view, only parts of them are clickable in the simulator. Is this because of Apples style guidelines? I placed a button exactly where a UITabNavigationItem would appear and only the bottom half of it is clickable.