How to tell if friend is in battle or not

When I see a friend is online in War Thunder, I can send a message or invite, but that is so easy to miss. The only way to get their attention is to send the invite when they are not currently in battle. I seem to recall that at one point I could mouse over their player card, and it would say something like, "In menu," or "In battle over sandlands" or something, but now I get nothing. How do i tell if their in battle or not, or if they are playing the game or just happen to have the game up?