birdtray

> Inability to minimize to tray on Linux Birdtray [1] works perfectly for this. I think the only thing you have to is create a .desktop file that opens birdtray that opens Thunderbird automatically. > Inability to easily edit the from address There is a feature for this for quite a while. In the write message window, just click the down arrow next to 'From' and either choose a pre-configured identity [2] or click "Customize From Address" which allows you to freely edit the from address. > And TB still doesn't "remember" which -from- addresses are used by which -to- address. Not sure what you mean, but there is a 'Reply from this identity when delivery headers match' config in account settings. I have never used it, but it allows you to automatically choose an identity when you are replying to a email from a particular address/domain. [1]

Not implemented in thunderbird, but take a look at birdtray to get that behavior. https://github.com/gyunaev/birdtray It's made to replace the old firetray extension.

Birdtray extension (https://github.com/gyunaev/birdtray) does that work quite well, I'm so happy with it. It also lets you keep Thunderbird as a background process.