#Librewolf update, now has a transitional background color on private windows.
If anyone knows how to change that, please let me know.
I tried setting custom colors but it does not work. Couldn't find anything obvious in about:config either.
Why is it a big deal? Because I have letter-boxing turned on and now I have bright purple lower-left corner and darker upper-right when browsing...it's irritating and distracting.