bug#8397: 24.0.50; defcustom :type face

[Drew Adams]

> > Prior to Emacs 22, you could simply click the `Select Face' 
> > button and then use TAB completion to see all faces and
> > choose one.  IOW, that button prompted you in the minibuffer
> > for the face name, and hitting TAB immediately (no need to
> > type anything) showed you the names of all faces.
> >  
> > Starting with Emacs 22, you must type some text into the face-name
> > field, then hit M-TAB.  So you must know some of the face 
> > name ahead of time, instead of simply seeing all names as a
> > reminder.
> 
> I don't see the problem: when the field is blank, M-TAB shows 
> all faces as completion alternatives.  There is no need to
> know any face name ahead of time.

I'm afraid my bug report isn't clear enough.  And it's been so long that I
cannot recall just what I had in mind wrt the Customize page in question.  I
don't know how to get to the field or button I reported about, unless what I
meant was the `Face:' field and `Select Face' button (for Emacs < 22) that is
associated (only?) with the `Inherit' field.  Do you happen to know ;-) how to
get to such a field/button otherwise?

If what I meant was only for `Inherit' then I agree with you that hitting M-TAB
with an empty edit field (empty input) does show all face names as completion
candidates. I don't know how I saw something different, but maybe that was the
case for an earlier Emacs 24 build or something - dunno.

FWIW, I still find the minibuffer completion easier than what M-TAB provides,
but that might be a personal preference.

One difference is this:

If you make the *Completions* window dedicated (e.g. (setq
special-display-regexps '("[ ]?[*][^*]+[*]"))), then M-TAB switches the focus to
the *Completions* frame each time you hit it.  That means you cannot just
continue to type text into the edit field - you must first reselect the
customize frame to give it focus.

With minibuffer completion, the same thing happens when the *Completions* frame
is first shown (created), but you only need to reselect the customize frame once
- thereafter you can continue to type into the edit field and hit TAB to update
*Completions*.  If you try to do that in Emacs 22+, each time you hit M-TAB the
*Completions* frame gets the focus anew, forcing you to reselect the customize
frame to type more text into the edit field.

I don't really have anything more to say about this bug.  If you feel like
closing it, go ahead.

However, there is an Emacs 24 bug here.  I tested the above with Emacs 22.  When
I try the same with Emacs 24 I see this problem:

M-TAB does NOT update *Completions* after you type more input in the edit field.
More precisely, with point at the end of your input it does not. You must move
point back to the _beginning_ of your input, and then hit M-TAB, to get the
completions of your input to show in *Completions*. I filed this as a separate
bug, #10721.  This is a regression wrt Emacs 23, which behaves normally.