In relation to Bug#5268 (23.1.90; # of rows/columns not adjusted by
change of internal-border-width for fullscreen frames), I found that
change of vertical-scroll-bars does not update the frame parameter
`width' for full screen frames. The value of (window-width) and
appearances look correct, though.
Steps to reproduce:
1. emacs -Q
2. (set-frame-parameter nil 'fullscreen 'fullboth) C-j
3. (cons (frame-width) (window-width)) C-j
=> (176 . 176)
4. (scroll-bar-mode) C-j
5. (cons (frame-width) (window-width)) C-j
=> (176 . 179)