how to bury/delete *Completions* buffer after completion in shell mode

[William Brower]

Typically, with find-file or other commands that
spawn a *Completions* buffer, after completion
the *Completions* buffer is "buried." By "buried",
I mean the new window which holds the *Completions*
buffer is deleted. Or, the frame, split into two
windows on creation of the *Completions* buffer,
reverts to un-split - the state it was originally in.

Is the fact that this does not occur when in
shell-mode a feature?

That is, in shell-mode, I type z<TAB> at the prompt

[wb@chumley wb]$ z<TAB>

and a *Completions* buffer is created and my frame 
is split in two windows, shell on top, *Completions* on bottom.
The latter looks like

Click <mouse-2> on a completion to select it.
In this buffer, type RET to select the completion near point.

Possible completions are:
zcat                               zcmp
zdiff                              zegrep
zeisstopnm                         zfgrep
zforce                             zgrep
zic2xpm                            zip
zipcloak                           zipgrep
zipinfo                            zipnote
zipsplit                           zless
zmore                              znew
zsoelim

I then type 'n' and hit <TAB> again to uniquely select 'znew'.
The prompt shows 'znew', good. The modeline echos 'Completed' - good.
But the window holding the *Completions* buffer is still there.
I would think my screen should revert to a simple one-window
frame as it was when I started.
This is how, say, find-file works. Why not shell-mode?

Any help?

Thanks,
Bill

For another approach, try the following to witness
the different behavior of the *Completions* buffer:

% emacs -q --no-site-file

M-x s h e l l <return> z <tab> n <tab> <return> 

(*Completions* buffer still in frame)

% emacs -q --no-site-file

C-x C-f <backspace> <backspace> / u s r / b i n / z <tab> n <tab>
<return>

(/usr/bin/znew loaded into only window as *Completions* buffer
is "buried" - no longer in the frame)