Or even just a tooltip when you hover over a system that tells you how many habitats you've built, out of how many open spaces. Like "x/y Habitats built."
It's annoying when there's a tiny celestial body at the edge of a system that could have a habitat built over it, that you completely overlooked the first time because it was obscured by something else, or was off the edge of the screen.
At the moment, I really don't like using habitats because I'm always second-guessing myself if I've built it in the right place. It's a lot of alloys, and construction time, only to find out I clicked on the wrong thing and now I have a habitat that isn't over anything useful. I'd rather not have any habitats at all in that case, because at least that way it's consistent.
The current system of building habitats without any organisation just REALLY frustrates me right now.