RE: [External] : Re: Strange whitespaces.

[Drew Adams]

> > I don't think the EN SPACE is displayed that way.
> > Not with `emacs -Q' (no init file), at least.  But
> > I don't have an Emacs 28 prerelease build - maybe
> > they changed Emacs 28 to highlight that as well.
> 
> They did.  We now highlight any non-ASCII character whose Unicode
> general category is "Space Separator" (or Zs for short).  That
> includes EN SPACE.
> 
> > Note that `nobreak-char-display' highlights all
> > no-break (aka "hard") characters, not just the
> > no-break space.  IOW, it highlights hard hyphens
> > (code point 8209) as well as hard spaces.
> 
> It highlights much more [in Emacs 28], see above.

All the more need for an ability to highlight or
not highlight individually.

Treating all such chars the same might be handy,
but it's also a limiting, all-or-nothing choice.
If you want different treatment for different chars
then it doesn't fit the bill.