(Vit)ality is a plugin that makes (V)im play nicely with (i)Term 2 and (t)mux.
Vitality restores the
FocusGained autocommand functionality.
Now Vim can save when iTerm 2 loses focus, even if it's inside tmux!
It also handles switching the cursor to a bar shaped one when in insert mode, and restoring it when not.
Pull requests for other helpful behavior are welcome.
Use Pathogen to install.
You shouldn't need to do anything else, but you can read
:help vitality if