logout before shutdown with shutdown button in XFCE
 

edit: Nevermind. For some reason it does what I want it to now. I have no idea why it didn't before, but I'm not going to touch it.

This is not a zero-reply thread...

I haven't seen that but occasionally the Quit panel item produces logout instead of the Log Out, Restart, Shutdown etc window. The workaround is to use Alt+F4 on the desktop.

Another occasional Xfce glitch on my systems is that sometimes clicking Thunar's file properties' Permissions tab crashes Thunar.