Subject: 24.3.50; `set-window-scroll-bars` has no effect after you set it once to zero

From: Drew Adams <[email-masked]>
Date: Thu, 16 Jan 2014 20:03:45 -0800 (PST)

emacs -Q

M-: (set-window-scroll-bars nil 0)

The scroll bar disappears.

M-: (window-scroll-bars) 

returns (0 0 nil nil)

M-: (set-window-scroll-bars nil 20)

has no visible effect.

M-: (window-scroll-bars) 

still returns (0 0 nil nil)

Toggling `scroll-bar-mode' any number of times also has no effect.

While I'm at it: a doc bug for `window-scroll-bars': There is no
description of any of these terms that are introduced, hence there
is no real description of the return-value: zero information, other
than it being a list of 4 elements):

WIDTH
COLS
VERTICAL-TYPE
HORIZONTAL-TYPE

For a function that *gets* some information, this doc string tells you
almost nothing about what that information is.

In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2014-01-07 on ODIEONE
Bzr revision: 115916 [email-masked]
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/binary --enable-checking=yes,glyphs
 'CFLAGS=-O0 -g3' LDFLAGS=-Lc:/Devel/emacs/lib
 CPPFLAGS=-Ic:/Devel/emacs/include'