Re: customize

[Richard Stallman]

    it is supposed to configure the trailing-whitespace face, activated by
    setting show-trailing-whitespace to a non-nil value; however, it sets
    the face to always have no attributes set.  This appears consistent
    with what it *does*: the face is just ordinary background, making the
    trailing hspace (which, for me, is actually blackspace, not
    whitespace; I use reverse-video systematically) invisible despite
    being `shown'.  This is perfectly correct behaviour.

Ok.

      If this is what customize is meant to do in this case, please
    could we have a control on the GUI that says `customize back off here
    and say nothing about this face' for use by those who want to do this
    via our own elisp.

That is the Erase Customization button.  It is supposed to put any
face or variable back in its standard settings.  However, I just tried
that and it didn't work for faces.  I fixed several bugs in that
feature.  Now it removes the info about that face in .emacs.

I also fixed it so that if the face is in its standard state, and you
do Save for Future Sessions, it saves nothing about that face.