Folder Pane View Switcher 6.1
by Jonathan Kamens, Arnd Issler
Folder view arrows; switch to "All Folders" view when hovering during drag & drop; allow user to select which views are enabled or tied to the view arrows.
About this Add-on
This add-on adds arrow buttons at the top of the folder pane which rotate back and forth through the various available folder views
This add-on also causes Thunderbird to automatically switch to the "All Folders" view when you hover over the title above the folder tree for several seconds during a message drag & drop operation, and switch back automatically after the drop. In the add-on preferences, you can set the delay before the view is switched.
Finally, in the add-on preferences, you can select which views are accessible in the pop-up menu at the top of the folder list, and of those, which show up when you rotate through the views using the arrow buttons.
Compatibility notes:
If you want to use this add-on with versions of Thunderbird prior to 49, you will need to download version 1.14. This older version does not have the ability to control which views are enabled.
This add-on is incompatible with the "Maximize Message Pane" add-on.