[lubuntu] Japanese input not working

I am an English speaker who often writes in Japanese to friends, etc. I am finding that my Lubuntu 16.04.1 LTS install has a weird bug that's frustrating the hell out of me: it doesn't seem to remember my switching the input method from the default, "none," to fcixt or ibus. Nearly all the instructions I can find online say "Go to Preferences, Language Support, and choose either ibus or fcixt, logout, then log back in."

But when I do that, the same "none" is back, always preselected. Any settings I change require relogging in...which means they vanish.

I can see the nice input window sitting there. But it just doesn't DO anything...I hit "cntl-space" and it appears or disappears, but never allows me the option to write anything but English/romaji.

Anyone know what's causing this?

Thank you!