When hovering the mouse over an orbiting object, the current altitude and speed are shown. I think it would be useful if some additional information were shown, e.g., current angular velocity and duration of a full orbit. That might help with approach manoeuvres for a rendezvous. Also, if several orbital reference points (apo/periapsis, intersections) are close to each over, the mouse-over texts of them are printed in the same place, making them hard to read. For orbiting objects, they are printed beneath each other, like a list. I think that would be nice for the reference points, too.