RE: patch for buff-menu.el enhancements

[Drew Adams]

>    ! If `Buffer-menu-use-header-line' is non-nil, you can click a
>    ! column heading to sort by that column.
>
> _Without_ your patch, you can do that even if
> `Buffer-menu-use-header-line' is nil.  Disabling the feature in that
> case is definitely not improvement; in fact I consider it a bug.

I disabled nothing of the kind. The doc string was incorrect, sorry. Here's
the correction: Please remove the phrase "If `Buffer-menu-use-header-line'
is non-nil, ".  Thanks for noticing that.

> I do not understand _why_ you want to reimplement the existing feature,
> which seems to work perfectly fine to me and also plays well with
> autoreverting the buffer menu.  (I did not check if your
> reimplementation does.)

Please try it.  I don't think I did what you suggest.  There is no problem
reverting the buffer. Reverting changes nothing; the current sort is
maintained.

FWIW, I proposed essentially this same patch back in 2004. I updated it for
the latest version of buff-menu.el. See, for example, these threads:

* 2004/10/16, "buff-menu.el - minor enhancement to sort
  columns up or down"
* 2004/11/19, "buff-menu.el header line"
* 2005/11/28, "Buffer listing in multiple frames/ttys"
 (related wrt sorting)

The only changes from vanilla Emacs wrt column sorting that my patch makes
are those I mentioned, in particular, (1) being able to sort in either
direction, (2) indicating the current sort column and sort direction with an
overline/underline of the column heading, and (3) being able to also sort
column `CRM' (one direction of which is the default sort).

For those who use Windows Explorer, you will recognize this
click-column-header sorting; you probably use it many times a day. IMO, it
is one of the most useful features of Windows Explorer. I think we should do
the same thing for Dired.