Shoutbox

I have one contact, whose Plus options are disabled. That means, that Display on Desktop, Events Notifications, Open Chat Log, Contact Information are gray for this contact (i cannot click on them).
I've checked every other contact i have, and these are working just fine.
I've asked that person, and he doesn't have any idea why is that happening.

Any ideas? Thanks

P.S. I tried deleting and re-inviting, in case that fixes the problem, but it didn't.