[Client] Moving Friends to New Group Deletes New Group

Main:

I can create a new group, name it whatever, all peachy. When I try to actually move someone to the new group, the client lags badly, usually to the point where it crashes. After I log back in (or wait a bit if it didn't fully crash), the new group is gone and the friend is back in the original group.

Stuff that might help?:

• Close to 300 friends if not at 300
• 17 groups in place (not counting new group attempt)
• Average PC specs, Windows 7, at least 60 fps in game

Other things:

• Lags when moving groups up or down, sometimes crashes

EDIT: Upon logging back in, I noticed the new friend group is now there. I'm not sure whether it was simply by relogging or because I removed some players and one existing group, as I'd already done both steps by the time I noticed it.