bug#6616: S-TAB is mismapped in the *Help* buffer

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 11 Jul 2010 23:20:22 -0700
> From: Paul Griepentrog <pgriepen@gmail.com>
> Cc: 
> 
>   The manual, (info "(emacs) Help Mode"), says "S-TAB"
> moves the point to the previous cross reference when in
> the *Help* buffer.  But, trying from a default emacs
> shows "S-TAB" is translated to "C-y":
> 
>      emacs -Q
>        ...                 ; Get to a *Help* buffer
>      C-h k S-TAB
> 
>      C-y (translated from <S-tab>) runs the command yank, which is an
>      interactive compiled Lisp function in `simple.el'.

This is Mac-specific, and it is due to this line from term/ns-win.el:

    (define-key map [S-tab] [25])

I have no idea why this line is there, perhaps Mac users expect this
binding.  I also don't see how this line plays with the following line
from the same ns-win.el, a few lines up:

    (put 'S-tab 'ascii-character (logior 16 ?\t))

These two lines have been there for almost 2 years.

> My guess is that the right place to change this is in the
> `button-buffer-map'.

No, the right way seems to be to find out why ns-win.el defines this
strange mapping.  Adrian?