I looked into this at one point. IIRC it turns out control mode was only added to tmux by the iterm2 dev, for use in his own project. So I guess he didn't care

I looked into this at one point. IIRC it turns out control mode was only added to tmux by the iterm2 dev, for use in his own project. So I guess he didn't care about adding support to tmux itself.