tmux plugin sets window-name to CWD

Some time ago my tmux window names went from being set to the current working dir to just showing 'zsh' (or whatever command was currently running). I did some investigating, and I think that the escape sequence for setting a tmux window name is different than that for setting an xterm title. I don't know if this changed in a recent version of tmux (I'm on OSX, and installed tmux 1.8 using homebrew).

Mike