Very simple, very effectively. Rated 5 out of 5 stars

This is exactly what I am missing in Thunderbird. Very simple to use and very effectively. I don't need to click-and-click if I want to see "unread messages" and "full mailbox tree". Everything is on my screen. And next improvements? I can suggest only to add possibility to show more then two panels. Great plug-in to great mailbox client.