Wolkom by Thunderbird Add-ons.
Foegje ekstra funksjes en stilen ta om Thunderbird hielendal fan jo te meitsjen.
SluteOer dizze add-on
The icon location can be adjusted by right clicking on the top bar of the main window then select Customize...
The default shortcut is Ctrl+T, but it can be changed to something else from the extension shortcut manager.