Hi PaQ, cool idea!

My main question would be, do you find yourself needing to create groups and change their colors on an extremely frequent basis?

I would probably reserve that kind of specialized in-viewport type display for something that would need to be used very frequently.

If it is something that you are going to use only once every 10 minutes or so, then it doesn't have as much of a payoff to make a super optimized "at your fingertips" type mechanism for it instead of something that may take an extra couple of seconds, like going off to the side instead of the UI for it being directly in the viewport...

- Michael