[Evolution] All messages in newsgroups (subscribed folders) disappearing?

[Jeff Evans <jwevans1 uiuc edu>]

Hi, 

I am running into a problem where sometimes the contents of my
newsgroup folders (added using Folder/Subscriptions for the
newsgroup account) lose all their messages when selecting the
folder.  All the messages disappear, and unsubbing/resubbing
doesn't fix the problem.  If I delete the account, re-create,
and re-subscribe, the message counts now show up correctly. 
However, when clicking the folder, the problem again
manifests.  I suspect it's a problem with the news server, but
this behavior still persists even after the server has
supposedly been "fixed" (it's happened a couple times).  Is
there any way to force Evolution to re-check the newsgroup for
all messages, every time, or on demand, ignoring whatever it
thinks it knows about what messages exist? Thanks.