When I add tap to a group, the first time I see the nice background animation, but afterwards I don't see anything. I do get the "tap!" printed to the log, so I know the tap is being registered. I'd be happy to submit a pull request if you can give me a hint where to look.
group.onTap { _ in
print("tap!")
self.valueBG.fillVar.animate(from: Color.white, to: Color(val: 0x333333), during: 0.1)
}