I recently changed news servers. Set $NNTPSERVER to the new server, started
up emacs/gnus, did 'b', then got used to the new article counts.

I subscribed to some newsgroups that were only on the new news server, by
doing 'B RET nntp RET (etc.)', then toggling subscription on the ones I
want and quitting out of the browse session. However, sometimes when I get
new news/mail with '3 g' or just 'g', I get this backtrace. Quitting it and
trying again will allow me to proceed without a failure.

Signaling: (error "Selecting deleted buffer")
  nntp-retrieve-groups(...)
  gnus-retrieve-groups(...)
  gnus-read-active-file-2(...)
  gnus-get-unread-articles(3)
  gnus-group-get-new-news(3)
  call-interactively(gnus-group-get-new-news)

I'm running Gnus 5.8.7, emacs 20.7.2 on debian linux. I have a moderately
tweaked .gnus. I've attached a neutralized copy of it.

What's up?

morgan