Changing the key mapping in Lubuntu (LXDE)

If you need to change the key mapping, like for example bind or unbind certain keys, the configuration file is located at:

~/.config/openbox/lubuntu-rc.xml

I for example had to unbind the ALT key, as it was conflicting with VirtualBox. The ALT key bindings are called A-Up and A-Down. It should be easy to figure out the rest.

After changing the file, don't forget to restart your session by either logging-out and back in, or restarting the system.