[CentOS] Apps moving to laptop display when switching KVM

Mon Nov 27 15:43:06 UTC 2023
Michael B Allen <ioplex at gmail.com>

UPDATE:

Apparently this is a long-standing and pervasive issue in the mutter package:

https://gitlab.gnome.org/GNOME/mutter/-/issues/1419
https://gitlab.gnome.org/GNOME/mutter/-/issues/230#note_1551972
https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2092
https://gitlab.gnome.org/GNOME/mutter/-/issues/1418
https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1778983
https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1574251
https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1927948

The second link has an explanation that sounds plausible.

The issue can occur under a wide range of circumstances from
suspend-resume (which I have since witnessed) or just locking the
screen and not just when KVM switching a KVM.

Unfortunately there is zero activity on the issue.

Mike

On Sun, Nov 26, 2023 at 9:44 PM Michael B Allen <ioplex at gmail.com> wrote:
>
> So I installed CentOS Stream 9 on a new Lenovo T14 Gen 4 Intel.
>
> I have a 4x1 HDMI KVM with external monitor.
>
> When switching the KVM, apps move between displays / workspaces in erratic ways.
>
> More specifically, when switching out, apps on the external display
> usually move to the laptop display.
>
> This sorta makes sense for a laptop with an external display.
> When the external display is disconnected, you want to have access to the apps.
>
> But for a KVM, the desired behavior is that the apps do NOT move.
> When switching back, I want all apps (terminals) to be where they were
> when I switched out.
>
> After much searching, I have found NO discussion of this issue.
>
> Is this a scenario that is even supposed to work?
>
> The KVM worked perfectly with the Windows 11 install that come with
> the machine (apps on the external display did not move when switching
> the KVM).
>
> Questions:
>
> Is there a GNOME window manager configuration that does not move apps
> when it senses the HDMI connection has changed?
>
> I actually had this mostly working with a Dell laptop running a RHEL 9
> clone and selecting Xorg on the GDM screen.
> Apps were not moved when switching out (although depending on
> particular circumstances they could when switching back).
>
> Where should I be asking about this?
> A freedesktop.org list?
>
> Where is the code that moves windows in reaction to a change in displays?
>
> Currently the only way to reliably switch the KVM without all of the
> apps loosing their positions is to just suspend the machine before and
> resume after.