I have not heard of such a problem.
I would doubt it is a problem with the stair tool as if it were there would be thousands of others here saying the same thing.
I would suspect a problem with you machine or the installation of the software.
Make sure you have the latest update for Archicad.
Are your machine drivers (video in particular) up to date?
What are you machine specs and operating system?
What version of Archicad are you running?
And I don't like to ask this but do you have a legal license for Archicad - not a cracked version?
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11