Windows move to different monitor when multiple monitors turned off and back on

[Rich Wales]

Ubuntu 19.10, gdm3 3.34.1-1ubuntu1, cinnamon 4.0.10-2, cinnamon-screensaver 4.0.3-1, nvidia-driver 435.21-0ubuntu2.

I have a TV set connected to my computer as a second monitor (for displaying YouTube videos, etc.).

When I turn off both my main monitor and the TV for the night, and turn them back on in the morning, I often find that the windows I had left open on the main monitor (email, browser, xterm, etc.) have moved from the main monitor to the TV and need to be moved back individually to the main monitor (via the "move to the other monitor" function on the taskbar icons).

This doesn't always happen -- sometimes the windows show up on the main monitor where I left them the night before, and sometimes not. Maybe 50-50, one way or the other.

The main monitor is configured (in the Display settings) as the primary monitor, and the taskbar panel remains on the main monitor -- and when I wake up the screen saver to unlock it, the password dialogue always shows up on the main monitor -- but the windows may end up on either device after I've unlocked.

It doesn't appear to make any difference what order I turn the monitor and the TV off/on. In particular, I've conscientiously turned off the TV before locking the screen and turning off the monitor, and then turned on the monitor and unlocked the screen before turning the TV back on, but the windows frequently still end up on the TV instead of the main monitor.

I would like to somehow flag the windows so that they will stay put on my main monitor when I turn things off at night and turn them back on in the morning -- or, even better, I would like the windows to remain associated with the same device and not move around on their own.

[Rich Wales (richw)]

I note this bug has been classified as affecting Compiz. However, as best I can tell, Compiz is not running on my computer. /etc/X11/default-display-manager on my computer contains the value "/usr/sbin/gdm3".

[Rich Wales (richw)]

I don't think Compiz is relevant here. My computer isn't running Compiz — its display manager is GDM3 as best I can tell. (<email address hidden>, the original reporter of this bug)

[Rich Wales (richw)]

Still having this problem. I'm temporarily working around it by disconnecting the HDMI cable from the computer to the back of the TV when I'm not actually playing something on the larger screen, but this is clearly not acceptable as a long-term solution.

[Rich Wales (richw)]

Noting once again that I am still having this problem. I am worried because no one seems to be working on it or have any idea how to work around it (other than by disconnecting the cable from my computer to the back of my TV when I'm not playing something on the TV screen).

[Joshua Peisach (itzswirlz)]

Hey, does this relate to you?

https://github.com/linuxmint/cinnamon/issues/9468
https://github.com/linuxmint/cinnamon/issues/9401