Groups will not stay in topic

[Colin Baxter <m43cap@yandex.com>]

I have several topics, and in my ~/.gnus.el they are arranged according
to:

--8<---------------cut here---------------start------------->8---
(eval-after-load 'gnus-topic
  '(progn
     (setq gnus-topic-topology
           '(("Gnus" visible) ;; root
             (("topic-1" visible nil nil))
             (("topic-2" visible nil nil ))))
     (setq gnus-topic-alist
           '(("topic-1" ; key of first topic
              "group-1"
              "group-2")
             ("topic-2" ; key of second topic
              "group-a"
              "group-b")
             ("Gnus")))))
--8<---------------cut here---------------end--------------->8---

I have more than two topics and four groups so the above scheme is
generic only.

Everything works well except for three groups in the final topic. These
groups will only stay in the topic area during the session in which they
were placed. In a new gnus session they have jumped out of the topic and
are visible just below the root "Gnus" but before the first topic. No
matter how often I return them using "Tm" to the last topic they will
have jumped out in the next session.

I can live with it, I suppose, but does anyone recognises the issue and
suggest a solution?

Thanks.

Colin Baxter.