"ghost" nnimap group with topics

[Steinar Bang <sb@metis.no>]

If you take a look at 
	http://www3.metis.no/private/sb/misc/gnusghost.gif
you will see the group "nnimap+tyr:imap/metis.alle" in two places. 

One is in the top level topic.  This is the "ghost" I'm talking about.
If I kill this entry, it is back the next time I do a get.

The other one is under the [Metis] topic, which is where I want it.

I usually subscribe to a nnimap group by browsing the server (I must
do it that way, if I wish to subscribe to a group with spaces in its
name). 

When I come back to the *Group* buffer I have two entries for the
subscribed group.  One of this entries replaces the metis.alle
"ghost".  When I kill one of these groups to move it to a more
appropriate place, the other one disappears.

After the next "g", metis.alle is back.

Any ideas of how to remove it permanently?