Never a problem here using Ceni in a Trinity session. I don't use any
other network setup apps, only ceni, wpa_gui or manual configs.

Ceni should be called in a root terminal. It should not matter what
desktop. What actually happens when you run it in Trinity?

Regarding wpa_gui, it's really good if you use more than one network.
Once setup it just connects automatically to the first available. A
user can edit/add networks quickly and easily. It has scan function
also. It's qt4 but doesn't need many deps

But it doesn't configure your interface, just networks. You have to
edit /etc/network/interfaces and
/etc/wpa_supplicant/wpa_supplicant.conf manually one time only.

Offtopic for this thread, but are you saying you can use kdesu (it's
not a package in itself) without a problem,?

I cannot without the fix I mentioned before, it crashes kdeinit. With
or without sudo-trinity installed.

For example, how do you open kwrite, konqueror, kuser, synaptic or
other X apps as root?