What is this highlighted face and how do I de-highlight it?

It’s annoying. Especially because I don’t know what it does.

last selected face

and nothing to do about it

happy 2.6

If that highlight is only for “last selected face”, I think it is not only pointless, but also annoying. It got to be useful, or simply should be removed. More importantly, it cannot be de-highlighted?

well it is the remnent of the last selected face which happen to be the active face too

but it appears like that even if de selected but does not influence anything in the render
it is only visible in the viewport

only way to change it is to select another face on an another object LOL