Rated 4 out of 5 stars

I like this Add-On allot! What would be really cool is if one could choose to set all mails from *all* accounts to "read", not just the active one. Use case: I have an IMAP mail account on which mails are deleted after 45 days. So I copy all mails by a filter automatically from there into a local mailbox, on which I normally read my mails (here, they aren't deleted). When I now click on "Mark all read", it would be cool if all mails in all folders of my remote IMAP-account would be set to "read", too - although my local mailbox is active.