Good add-on, but wrong approach Rated 4 out of 5 stars
It does the job as stated. However, I think this add-on takes the wrong approach. Instead of "Send and Archive", it should be "Reply and Archive". As it is, users have two options to send; I'm with a previous reviewer who stated that they forget to use this button. Sometimes we wish to send (i.e. when we start a new thread), and sometimes we wish to send and archive (i.e. with replying).
With "Reply and Archive", this would link the archiving to the reply action. *Everytime* I reply, I wish to archive. Users could replace the reply action with this custom action in all cases.
Regarding keyboard shortcuts, I had a look here: http://kb.mozillazine.org/Keyconfig_extension
I tried `goDoCommand('cmd_sendAndArchive')` and `cmd_sendAndArchive`, but neither worked for me.