Here's a complaint/suggestion for the developers of SeaMonkey...

Since it is not possible to get messages from a single newsgroup in an
account that contains a number of subscribed groups, it ought to be
possible to mark all newsgroups read.

For instance, I have subscribed to eight newsgroups at cnews.corel.com.
When I open the Corel.com account, all eight newsgroups immediately
update with new posts. sometimes i don't want to read every
newsgroup...but I don't like having to select each group individually
and mark each as read separately, either.