I'd like to create a small niche on the side of a wall opening. I created it using the niche command like in the plan below.
But the 3D shows a fake line with zero thickness but visible.

Is there any trick to do it? I already tried without success to:
- enlarge a bit the niche beyond wall opening: still visible
- create first the niche: cannot create the wall opening
- create a niche larger than the walll opening: cannot insert it
- edit the room with interion modeling (1.0 or 2.0): cannot edit the wall inside itself but extrude inside the room

