Subject: 26.0.50; display-buffer doesn't set window width correctly

From: Liu Hui <[email-masked]>
Date: Sun, 11 Dec 2016 20:18:33 +0800

Recipe 1:

1. Emacs -Q
2. evaluate the following code in *scratch*:

    (display-buffer (get-buffer-create "aaa")
                   '(display-buffer-pop-up-window
                     (window-width . 20)))
    ;; => correct window width for buffer "aaa"

    (display-buffer (get-buffer-create "bbb")
                   '(display-buffer-pop-up-window
                     (window-width . 20)))
    ;; => changed and larger window width for buffer "bbb"

Recipe 2:

1. Emacs -Q
2. evaluate the following code in *scratch*:

    (display-buffer (get-buffer-create "aaa")
		  '(display-buffer-in-side-window
		    (window-width . 20)
		    (side . right)))
    ;; => correct window width for buffer "aaa"

    (display-buffer (get-buffer-create "bbb")
		  '(display-buffer-in-side-window
		    (window-width . 20)
		    (side . left)))
    ;; => correct width for buffer "bbb", but the window width of
    ;; buffer "aaa" is changed and becomes larger

In GNU Emacs 26.0.50.2 (x86_64-pc-linux-gnu, GTK+ Version 3.18.9)
  of 2016-12-10 built on lgw01-57
Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
System Description:	Ubuntu 16.04.1 LTS