I guess this is a bug but i actually think it could be a good idea. Attached are a couple of examples of what's happened on my screen from time to time. The UI takes on a florescent colour - and all palette names/numbers, etc change to this colour.
Small appearing UI's seems to have been quite a big topic in recent years - especially as we all move toward 4K screens. So this 'bug', if that's what it is, seems to work really well for me and gives the whole workspace much more clarity. But i just have no idea how i trigger it! I wonder if this could be useful to Adobe in solving a lot of people's criticisms lately?