Problem renaming groups

I have a strange issue every time I try to rename a group. For example, I create a new group directly beneath the root (Sessions) and name it Test. So now the tree looks like this:
Sessions
---->Test
When I press F2 and rename the Test group to something else, it creates another group named 0 and makes my original folder a sub-group of this new 0 group, like so:
Sessions
---->0
-------->Test Renamed
Now I can resolve this fairly simply by right-clicking on Test Renamed and selecting Move to Another Group/Folder and selecting to move it under Sessions. When I do that the group named 0 (that was auto-created) disappears and the Test Renamed folder goes where it should, such as
Sessions
---->Test Renamed
So it's not too much trouble to get things the way I want, but it sure would be nice to just be able to rename a group in place without always have to move it afterward. This happens no matter what level of the tree the renamed group is in, i.e. it could be a couple of levels deep in the tree and it will still create a "dummy" group named 0 and put the renamed group below that.
Any idea what could be causing this strange behavior?
Thanks - Jay