So for ages I have been using Thunderbird combined with server side mail sorting, what has been annoying me for a year or so is that Thunderbird only checks the Inbox folder. I had to manually check all the others and that got a little tedious, fortunately I discovered how to get around this.
The trick is to open the configuration editor (Edit -> Preferences -> Advanced) and set the mail.check_all_imap_folders_for_new preference to true. Bingo!
