Rated 4 out of 5 stars
It has potential, but the two buttons do NOT show up when Thunderbird first starts. Every morning, I need to go into Addons and disable and reenable the addon. Then the buttons show.
UPDATE: The buttons appear in the CUSTOMIZE list and one can drag them to the toolbar to the left of the three horizontal bar menu button and they stay permanently. GREAT NEWS.
When the buttons stay there, I'd give it a 5! The button to get to the folder menu is essential now that the Thunderbird Filter pane is two or three clicks deep. It's been getting deeper. Keep up the good work! Thanks for doing this.