Please! Same goes for cities without production. I keep missing those, too, when I could be building something instead.
Don't agree on that. For one, you already have the "zzz" that appears next to idle cities on the lists to the right, but also there are various times that unlike research, you actually don't want to be building anything. Like when you've got nothing you want to build, or when you have any of the improvements that gives you bonuses specifically when production is idle.
