linux - how do I influence the compose rules in gnome?

this is a partial duplicate of the question Linux 'compose' key sequence extensions:

I am using ubuntu 13.04 with unity and I would like to have a specific composition sequence to work as defined in the X11 rules ( produces now "ç") and to add a new one ( to produce "ʒ")

my ~/.XCompose contains both above rules, but the above behaviour is not here yet.

Answer

The default GTK input method, gtk-im-context-simple, uses a compiled-in list of Compose sequences. You will need to make it use the XIM module.

Add this line to your ~/.xprofile file, then log out and log in again:

export GTK_IM_MODULE='xim'

To undo, remove the line.