Subject: bug#40888: M-x man: don't redraw good pages when not finding bad pages

From: Tomas Nordin <[email-masked]>
Date: Mon, 27 Apr 2020 10:33:12 +0200

積丹尼 Dan Jacobson <[email-masked]> writes:

> $ emacs -q
> M-x man cat
> M-x man dog
>
> Why does it have to redraw the entire cat man page, before just saying
> it can't find dog? Why can't it just say it can't find dog?
> Just leave the good page there undisturbed.

I think it is fixed to work like that, it does here with 28.0.50.

Maybe this news item is relevant

*** New function 'display-buffer-reuse-mode-window' is an action function
suitable for use in 'display-buffer-alist'.  For example, to avoid
creating a new window when opening man pages when there's already one,
use

(add-to-list 'display-buffer-alist
     '("\\`\\*Man .*\\*\\'" .
       (display-buffer-reuse-mode-window
        (inhibit-same-window . nil)
        (mode . Man-mode))))

under the super heading * Lisp Changes in Emacs 26.1.

> emacs-version "26.3".

Confusing then. But maybe that function was used later for the man
rendering.