I will say; I did a page reload and noticed the color pick was still in place and had to go hunt for the x. I expected it to reset, but I'm not sure if you see that as a bug or a feature :)
also, it looks like the client side is pure js... Is Lumen not up to that task? just curious if you tried that as it might be nice if, someday, we could get to the point where this kind of stuff could be done in arc.