UITabBarItem not generating touch event

A bit of a mystery.

I have a UITabBar with开发者_StackOverflow中文版 4 items. Item 1, 2 and 4 work as intended. The third item somehow does not respond to touches, ie "- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item" does not fire when tapping it.

All four items in IB have the Enabled flag set to YES. User interaction is enabled for the tab bar itself.

Any ideas?

Is something on top of that part of the tab bar, like a button or image view near by?