Windows at edges of screen area shift down by height of panel after dpms wakeup
Fedora 41 XFCE 4.18.6 with xfwm4 4.18.0 (all stock Fedora packages)
4 monitors as follows:
3 Acer 1920x1080 over 1 Samsung 5120x1440
Panel at the top of monitor 1 (the primary) that's 48 pixels tall.
If I place windows at the top left of monitor 2 and the top right of monitor 4, when the monitors wake after dpms has put them to sleep, those two windows will shift down by 48 pixels (or whatever the height of the panel is). If I move them up again and do a xset dpms force off, they'll shift down again when the monitors wake. I ran wmctrl -lxG in a loop to log the window positions to make sure they were still at their correct positions during the sleep and only shifted on wakeup. The windows on the upper monitors that don't fall outside the horizontal bounds of the bottom monitor are unaffected.
Originally I thought it was devilspie2 that was going it then maybe workspace margins but after much experimentation I found it was having "Reserve space on screen edge for the panel" checked in panel preferences. Whether this makes it a panel issue or a xfwm4 issue, I'm not sure. There's no screensaver and sleep and hibernation are disabled. Only dpms is active.
Thoughts?
EDIT: Another tidbit. If I use ctrl-alt-fn to switch to another tty and switch back again. the windows DON'T shift. It only seems to be dpms that triggers the shift.