I've been attempting some systematic testing, which has narrowed the issues down a little:
Changing FieldBG to anything other than white is what blanks everything out on the Character/Item/Location tabs/windows. That part is 100% reproducible. It's also what's affecting the scene list window but
not always. Worst kind of bug to hunt down, I know.
Changing TextFG sometimes only changes the left hand side of the Character/Item/Location view, but again
not always. It's hard to be sure, but I think the issue with FieldBG is interacting somehow with TexttFG. Sometimes all of the text under C/I/L is the wrong color (not TextFG). Closing and reoping the program usually seems to sort that particular problem out.