You need to be running mutt inside a screen session for this to work
(you'd know if you were). If you haven't tried screen before, I suggest
you give it a go - it's a great little program. If you don't want to
use screen, you can probably get the same effect by changing the last
line of the script to something like:
xterm -e sh -c "mutt -f \"$BOX\" -e \"exec $1\"; rm -f \"$BOX\"" &
(though I haven't checked if that'll work exactly as shown)
- Andrew