I'm using XFCE on CentOS to make a kiosk. The only thing I have on the desktop is a panel on the top with some programs. It already auto-logins at boot and, at the end of the session, I want the user to be able only to shutdown. However, there is still a "log out" button when right-clicking the panel and I just can't find the configuration file to get rid of this button. I have already searched almost every config file but couldn't find one for the panel-right-click-menu. Another option I have is disabling logout entirely, but I don't know how to go about that.
XFCE4 is supposed to have a "kiosk" mode that lets you disable logout. Alternately, you can make the "Logout" command run shutdown instead. Here's an example from CCC at https://forum.xfce.org/viewtopic.php?id=6846:
Change the file
[Desktop Entry] Version=1.0 Type=Application Exec=/usr/bin/sudo /sbin/shutdown -h now Icon=system-log-out StartupNotify=false Terminal=false Categories=System;X-XFCE;X-Xfce-Toplevel; OnlyShowIn=XFCE; Name=Log Out