bug#35860: Delayed window positioning after buffer display

[Eli Zaretskii <eliz@gnu.org>]

> From: Juri Linkov <juri@linkov.net>
> Cc: 35860@debbugs.gnu.org
> Date: Thu, 23 May 2019 23:56:17 +0300
> 
> >>   ;; `help-window-point-marker' is a marker you can move to a valid
> >>   ;; position of the buffer shown in the help window in order to override
> >>   ;; the standard positioning mechanism (`point-min') chosen by
> >>   ;; `with-output-to-temp-buffer' and `with-temp-buffer-window'.
> >>   ;; `with-help-window' has this point nowhere before exiting.  Currently
> >>   ;; used by `view-lossage' to assert that the last keystrokes are always
> >>   ;; visible.
> >>   (defvar help-window-point-marker (make-marker)
> >>     "Marker to override default `window-point' in help windows.")
> >
> > Why not bind switch-to-buffer-preserve-window-point to nil instead?
> 
> I don't know.  I tried to replace
> 
>   (set-marker help-window-point-marker (point))
> 
> with
> 
>   (goto-char (point-max))
>   (setq-local switch-to-buffer-preserve-window-point nil)
> 
> and it doesn't set point to the end of the Help buffer
> when it's displayed for the first time.

Can you show a recipe starting from "emacs -Q" that exhibits this
behavior.  It sounds like I'm confused about what exactly happens.