Reported already in November 2024 for Cubase 14
→ still not fixed in C15.0.10.
(I am also on Windows 10)
Interesting… Mac or Windows? (which version).
Or maybe graphics card is to blame? Mine is NVIDIA GeForce GTX 1060 (latest Studio driver)
It’s Win10. I have a nVidia RTX2070.
No problem here either in C14 + 15 (Win11, Nvida GT 1030)
Also works fine here.
Win11 latest, Intel on-board graphics.
Thanks for all the comments.
I found out this; if I select any factory Preferences preset (Cubase 14 Defaults, Cubase Legacy) or if no preset is selected at all (meaning I only open Preferences), it’s OK.
However if I select any of mine Preferences presets, it’s broken.
Isn’t it weird? 
It would be great if it was weird but unfortunately it isn’t.
Cubase saves these and other preferences in several files. From time to time a user experiences that something went wrong when those files are overwritten (because of changes to the settings) and then Cubase starts to show all kinds of “wrong” behaviour.
When you use a different preset then Cubase replaces some of the files with the ones from the preset and the bad apple is thrown out of the basket.
If you browse the forum you will see lots of topics (too many for my taste) where people are asked to trash their preferences in order to fix issues.