Make "super/window" as compose key in Ubuntu

Question

Somehow on my new X230t Lenovo Thinkpad, Ubuntu 13.10 only lets me have the following options as the compose key:

Right Alt, Right Ctrl, Left Alt, Right Win, Menu, Caps Lock

I really don't care for Unity's functions using Super. I would like to set this as my compose key. Is there any way to manage this?

UPDATE: This solution had been working like a charm for me, until today when Ubuntu did a fateful update. I looked at the d-conf editor for the entry below. It still shows compose:lwin as an option. But Left Window is no longer available as an option in the keyboard settings. Any suggestions? (I am using Ubuntu 14.04 now)

Answer 1

You can do this through the dconf-editor. If you do not already have it installed, you can install it with:

sudo apt-get install dconf-editor

Navigate to org >> gnome >> desktop >> input-sources

Click in the setting, xkb-options and add 'compose:lwin' inside the square brackets. The single quotes are required.

If other options are already there, the order does not matter; but separate the options with a comma: 'compose:lwin','other:option'

For those who looks for a command line solution (without installing dconf-editor) you can use:

$ dconf read /org/gnome/desktop/input-sources/xkb-options 
@as []

This will tell you the current state of the key. Now you can insert your own:

dconf write /org/gnome/desktop/input-sources/xkb-options ['compose:lwin']

This command as above worked fine for me, but @bryce reports that he needed double quotes, as in:

dconf write /org/gnome/desktop/input-sources/xkb-options "['compose:lwin']"