Misc merge/small stuff from docking to reduce drift.

Among other things:
- merged cfd23957 (#7940, #7823), also see ac64b656 (#6716): moved above on 2023/08/14 in both branches.
- moving the RenderDimmedBackgrounds() call, from f422e782, see 676497fe intently undoing ac64b656 -> confusing. (#6716)