Robin
Many many thanks @abc-nix. That’s a great relief. It was a real annoyance to me for years, and I didn’t even know that this easy to access tickbox is related to it. It is simply impossible to read that feeble black text on my screens when all the tabs are dark red. And you are right, the bright red icon is reminder enough, in particular in combination with the fact that my default user has a dark theme and the root stuff comes always up with bright themed windows.
Windows is like a submarine. Open a window and serious problems will start.