bug#33442: 26.1.90; Cairo side-by-side windows scrolling fix should be cherry-picked

[Ari Roponen]

Dmitry Gutov <dgutov@yandex.ru> writes:

> On 22.11.2018 8:44, Ari Roponen wrote:
>
>> It does work here. I use gnome-shell on Xwayland.
>> Could you try the following patch, if it helps?
>
> No change.
>
> It's probably also related to HiDPI: the area that gets refreshed is
> at half the window size and height. And my desktop scaling factor is
> 2.

That seems to be it: Starting Emacs with
  GDK_SCALE=2 emacs -Q
shows the problem here, too.