Ah okay, so does the page in the new window display correctly or not?
Here it does not, and after the `print` then it gets displayed...
 
I have tried with Emacs 27.2 now, and indeed there this problem does not occur.
So it occurs in my build of Emacs 29. I will rebuild it using the latest version and
see how it works there.

Eli, thanks a lot for your help!

On Sat, 16 Apr 2022 at 21:33, dalanicolai <dalanicolai@gmail.com> wrote:
Ah okay, so does the page in the new window display correctly or not?
Here it does not, and after the `print` then it gets displayed...

On Sat, 16 Apr 2022 at 21:18, Eli Zaretskii <eliz@gnu.org> wrote:
> From: dalanicolai <dalanicolai@gmail.com>
> Date: Sat, 16 Apr 2022 21:16:18 +0200
> Cc: Emacs Devel <emacs-devel@gnu.org>
>
>  I guess I don't understand what you mean by "window does not get
>  redisplayed".  because I see no difference on display before and after
>  I do 'M-: (print "test")'.  Maybe I didn't follow the recipe to the
>  letter?
>
> Did you scroll forward a few pages before splitting the window?

Yes.