Sorry if i am behind, but with WB11 we can no longer change the Explorer Background colour like we could in WB 10?.
Every single skin i use i do this too it as do not like none black backgrounds, old eyes, well this is a step backwards.
I believe, based on communicating with them through a ticket, they are asking about a "split background" explorer window option that went away when Microsoft introduced Light/Dark mode (if my info is correct), where the left side is one background color and the right another.
NOT that it can't have any background color at all, it can.
Associate Technical Support Analyst