Lo Peter <peterloleungyau@gmail.com> writes:
> Any help is greatly appreciated. Also, I think a way to let user
> customize /etc/environment through the system config will be useful,
> but I do not find a way to do so.

Try adding something like this to your system services:

(simple-service 'my-ibus-ch-env session-environment-service-type
                  '(("GTK_IM_MODULE" . "ibus")
                    ("QT_IM_MODULE" . "ibus")))
                    
-- 
Das Lernen vieler Dinge lehrt nicht Verständnis.
     Heraklit, B40