Trying to move an empty friend group deletes the group

My general group was getting too big, so I went to make a new friend group. Before I added any friends to the group, I tried to adjust its position on my list to where I wanted it [rclick -> move group down]. My client froze for a few seconds while it processed, and then the group was deleted. Adding a friend to a group before moving it fixed the problem. Bug is reproducible by creating a new group, then attempting to move it before adding any members to the group. OS is windows 7, if that is relevant.