I’ve highlighted four points (orange) that I’d like aligned horizontally, but the alignment tool is greyed out. How do I align these? tx
You draw a line between the two points (ideally a construction line), click that line and then click on horizontal/vertical. That constraint is made for lines, not points.
Add construction line. Make it horizontal and coincidence to highlighted points.
Or in your particular case you can make right points coincidence to axis and then make a mirror.
Got it, thank you.
Although the instructions I found said to make a normal line, then highlight it and click the Make Construction button. I couldn’t find a Construction Line icon, so went with that method.

