bug#8355: 24.0.50; Boxes in mode-line and scrolling

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: antoine.levitt@gmail.com,  8355@debbugs.gnu.org
> Date: Wed, 09 Dec 2020 18:01:44 +0100
> 
> I tried this on something that has more dramatic line height
> differences, and the phenomenon is more noticeable there -- when
> scrolling downwards, things are very predictable, but when scrolling
> backwards, Emacs seems to decide to scroll a couple of screenfuls when
> there's large images in the buffer, and you have to C-v twice to get
> back to where you were.
> 
> Should I make a test case?

Yes, please.