If you just installed scim, it will probably not just work when you press control+space. You need to have set it as a demon and/or help it a little bit by telling it when would be ok for it to appear.
I mean, do you have the XMODIFIERS, XIM_PROGRAM, GTK_IM_MODULE, and QT_IM_MODULE variables setted?
You could set them manually by:
Code:
export XMODIFIERS="@im=SCIM"
export XIM_PROGRAM="/usr/bin/scim -d"
export GTK_IM_MODULE="scim"
export QT_IM_MODULE="scim"
or if you plan to use scim everyday, you could write the same code above in a file called /etc/X11/Xsession.d/75scim <-the name of the directory might differ according to your distro/etc. Well, it would be as a daemon anyway so it would probably be a good idea.