I have an L-shaped staircase running from an inside room up to a room over the garage. I have the stairs set to "open underneath." How can I fill in the area that shows open banisters in the garage itself? (see red arrow on screenshot.) When I place a wall in the garage and try to re-shape it to fit that triangle, the sole plate shows on the bottom of the wall segment. Any ideas?
stair tester.plan