tmux actually tries to be clever here and guess if you're a vim user or not: if your $EDITOR contains the string "vi", you get vi-style keybindings by default.

tmux actually tries to be clever here and guess if you're a vim user or not: if your $EDITOR contains the string "vi", you get vi-style keybindings by default. If it doesn't, you get emacs. But unfortunately it doesn't look at $VISUAL, so... yeah, you usually have to set it explicitly.