Thanks. Seems to be working now. How many slots can you get? I'm at chapter 10, and have Lv.4 technique. So I assume that should mean I have 4 slots? Don't know if it's just a problem with the UI, but I seem to only be able to send 1-2 people on missions. The UI seems to occasionally skip sending the second person when using clicks, and stops asking after the second person.
Edit: or are slots more a function of progress in the story, not so much technique levels? Early on you seem to only have one slot, regardless of level, but later chapters seem to allow the full 4 characters.