Hello, I'm trying to do `st -e "tmux a -t cmus"`
but it only gives me `child finished with error '256'`.
* `tmux a -t cmus` works perfectly in an already open st.
* `st -e tmux` works fine (there's an `erresc: unknown private set/reset mode
1005` message, though).
* `tmux new -A -s dash -d dash; st -e "tmux a -t dash"` fails (the problem isn't
in cmus).
* xterm works in both cases.
Tested with 0.7 and git.
