Virtualbox(-qt) gives bad graphics.
I think the problem started on tumbleweed 2019-08-29, with a plasma update, on TW 2019-08-09 didn’t gave this problem.
On TW 2019-10-03 downgrade virtualbox to virtualbox-qt-6.0.6-lp151.1.2.x86_64.rpm (from leap 15.1) gives still bad graphics.
Closed nvidia rpm drives inside (GTX 660)
Anyone the same problem?
created a new user, seems that the problem is gone.
Now i can go futher with the new user but i want to find the files that creates this problem.
file “.vbox” delete didn’t solve it.
I would think you might try asking this in this forum’s Virtualization section. It’s there for exactly these kind of questions. Maybe one of the admins might be able to move it there for you at your request.