Set compose key in Xfce

General help can be found on this article on Compose key. It didn't work for me however in Xfce.

The command

setxkbmap -option compose:lwin

works perfectly however. After this, I can for instance type the inverted question mark by pressing the left Windows key, releasing it, and then typing 2 normal question marks.

To make the command run at every startup, I did the following.

Make a file "setcomposekey.sh", put the following text in it:

#!/bin/sh
setxkbmap -option compose:lwin
echo "Compose key set to left Windows key."
sleep 2

and save the file where you can find it afterwards.

Then, in a terminal, navigate to the directory where you saved it, and type the command:

chmod +x ./setcomposekey.sh

to make it executable.

Now, go to Xfce "Applications Menu", choose "Settings" -> "Session and Startup", tab "Application Autostart", and add your little script to the programs to run at startup.

BTW, you have to do this for every user (login as that user and do the same routine).