We've been messing with the TabGroup focus/blur events and the Tab selected/unselected events:
TIMOB-18099deprecated TabGroup focus/blur for selected/unselected on iOS TIMOB-19759deprecated TabGroup selected/unselected, restored focus/blur and added selected/unselected for iOS
The API reference does not reflect this:
- http://docs.appcelerator.com/platform/latest/#!/api/Titanium.UI.Tab-event-selected (should include iOS since 5.2, also for unselected)
I think Windows also support focus/blur but I'm not 100% sure about that.