You can't copy and paste for security reasons. Think about it: every program
can access the clipboard, so could steal the private key and export it.
I have a password generated via the Diceware method:
http://world.std.com/~reinhold/diceware.html
This is secure and easy to remember, if you make
It probably was not a bug. Enigmail can integrate with Thunderbird's password
manager (and it has not had a major update in years). I'm pretty certain it
can do this in Trisquel.
For an alternate method to generate a password that is easy to remember
(several random words):
https://trisquel.info/fr/forum/what-are-your-favorite-encryption-programs-or-methods#comment-95966
Diceware is random, that's the whole point.
The command in the post I linked uses /dev/random (not /dev/urandom). It is
random. Maybe more random than the dices (whose output is determined by the
law of mechanics).
Unity shares a lot in common with GNOME Shell, so try that.