From http://bugzilla.gnome.org/show_bug.cgi?id=528352 :

yesterday i added some icq contacts (used via haze) to empathy and then i
wanted to sort them into a certain group.
they were all first in the group "buddies" as i added them in pidgin, since
nothing happened when i tried to add them in empathy :/

when i wanted to sort them (in empathy) it worked, IF i added them into the new
group first, before removing them from the group "buddies".
If i removed them from "buddies" first, so that they were in no group currently
and then tried to add them to the new group, the haze manager crashed and the
contact wasn't in my contact list anymore at all!

gajim has some kind of fall back group in which ungrouped contacts are put, so
that they don't get lost or whatever, but the current behaviour in empathy is
really, REALLY bad in this case. Using svn 947.