to show a habitable zone, click on an object. The toolbar on the right that pops up, i think the 2nd or 3rd? tab says habitable zone. Click on it and this green ring will pop up. Lagrange points are the 5 points an object will remain stationary compared to the other objects in orbit. For example, if you were on one of the lagrange points between earth and moon, they would always look the same to you. The same distance apart, same angle, same place in the sky