Is there a way in Thunderbird...

Back on topic, even better than the "order by unread" is the filtering options, there's a drop-down labelled "view" that's either on the thunderbird toolbar or available to place there and it allows you to specify what messages to show (unread, all, with attachments etc). I regularly do this to clean the spam I gloss over in batch instead of one at a time.
 
Back
Top Bottom