Created attachment 8778
The problem happened twice with me since I installed XFCE4 (installed the day before yesterday), and does not occur every time the alarm command is run.
My OS is Arch Linux.
My alarm command is set to "mpv /usr/share/sounds/freedesktop/stereo/complete.oga".
Before using it on the plugin, I ran the command in my terminal and it works.
Yesterday, the first time I've set the alarm command, my XFCE froze immediately after showing the alarm dialog and playing the alarm command.
When it freezes, every window becomes unresponsible, only the mouse cursor works, and the only way to recover is to open a new tty and run a command to reboot the PC.
Today I've set to not show the alarm dialog, but the problem happened again.
The problem seems to not happen when I do not set any alarm command. I'm trying to find what's the problem (missing packages or the stacktrace), but I need help.
I annexed the Xorg.0.log.old and a screenshot with the settings I used the last time it froze.
If there is any other log or output of command that is necessary, please tell me and I'll put here. I want to keep using this plugin, but this bug annoys me.
Not sure if it is related, but I use "nvidia-xrun startxfce4" on a console to start my XFCE session. If I do not use it, XFCE does not work at all for me (my monitor turns off - black screen).
This problem disappeared after I fixed my problems with NVIDIA and started running XFCE from LightDM.
Now that I think about it, this bug has very similar symptoms of #682. Probably its the X fault.
So I'm marking this bug as duplicated.
*** This bug has been marked as a duplicate of bug 682 ***