Love it. Awesome project. Simple as that.
Meanwhile… what would make my life so much easier right now is ACCOUNT REORDERING.
I’m increasing the number of RSS feeds I follow, for example. I cannot for the life of me get drag/drop to work and get them alphabetical order. There is no dragged ‘line’ where I might place the dragged acount.
Preferable would be something like CMD + Shift (or CMD + Alt) and up/down arrow. Or even a dialogue box to NUMBER ACCOUNT ORDER PREFERENCE. Or the dragging to display a LINE with the expected location to drop.
Wow if only I took that thought process one step further last week haha! At least in Windows 10, I’ve resolved this with the following steps to reorder accounts in Thunderbird:
- Account settings
- Highlight the problematic account and press Ctrl (edit: actually this key is optional) + Alt + Up/Down Arrow
- When the account moves one position the focus shifts to the account which replaced it. Just keep going back to perform step 2 until the account is in your desired list location.
Guiding text like this could do with being somewhere in that account management window? In retrospect I do see REORDER ATTACHMENTS listed in the Mozilla homed Tbird Keyboard Shortcuts list, just no reference to reorder accounts.
Edit: Escalated to UX (with vastly more details documented) and notified these problems already exist within BMO issues 1706849 and 1703501.
And already resolved. Team 
Mozilla Thunderbird was originally launched as Minotaur, shortly after Phoenix (the original name for Mozilla Firefox); the project failed to gain momentum. With the success of the Mozilla Firefox, however, demand increased for a mail client to go with it, and the work on Minotaur was revived under the new name of Thunderbird, and migrated to the new toolkit developed by the Firefox team.