User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:) Gecko/20040304 Build Identifier: Mozilla/5.0 (Windows; U; Win98; en-US; rv:) Gecko/20040304 I would like to use message filters based on headers other than Sender, Subject, and Date. It's already enabled for Email filters, but not Newsgroups. For example, I would like to write a newsgroup filter based on "User-Agent". Reproducible: Always Steps to Reproduce: 1. Go to Mail/Newsgroups component 2. Select a newsgroup 3. Go to Message Filters 4. Add a new rule 5. Select "Subject" and discover only three categories of filtering Actual Results: Limited to only those three categories (Subject, Sender, Date). Expected Results: At least add "Customize header" like there is for Email filters.

Dupe of bug 16913?

You can filter news for more categories - in offline mode. For online, IMHO bug 16913 is about customized header fields. That would also solve this bug, but isn't the same. I'd say this is a dupe to bug 178397.

See also bug 178398. *** This bug has been marked as a duplicate of 178397 ***