After a colour change, a restart of Rhino is currently required.
I agree, it is not a critical thing, since typically, you would either use Dark or Light. However it looks very unprofessional IMO similar to the general discussions on a less “tidy” UI in general in Rhino 8 (+ETO?)
Thanks Dan. I will consider this to be solved, maybe with the “program headline” as the only exception?
The titlebar issue is handled: