Welcome to Thunderbird Add-ons.
Add extra features and styles to make Thunderbird your own.Close
Rated 5 out of 5 stars
Works like a charm, particularly with my themes: LittleFox, Nautipolis, Walnut and Walnut2.
P.s. when closing the last tab (in CloseWithLastWindow=false), the tab shrinks and then reappears. This actually an issue in the tab handling itself, as a 'close' command on the last tab should not do anything.