I'm trying to create a visual indicator of which pane is currently focused in tmux when my terminal (iterm2, OSX) window gains focus. I have found that iterm2 sends a focus gained escape sequence (^[[I) so now I am trying to find how I can capture that and fire the prefix q command which shows pane numbers with the active pane in red.
Any ideas on how to capture the escape sequence in tmux OR in iterm2?
I have a partial solution to my issue which takes a different approach. Since I usually have vim and one terminal pane open, dimming vim when it is not focussed is a good indicator which pane is active. In order to achieve this I have modified the vim-diminactive plugin to react to focus events (https://github.com/blueyed/vim-diminactive/pull/8), this requires the Vitality.vim plugin as well as enabling (focus-events) in tmux options.
In order to completely solve my issue I am working on changing the background colour of terminal panes when they lose focus. I use zsh so I can capture the focus event with bindkey (I have verified this works) to issue a background colour change escape code to iterm2, however this seems to have no effect in tmux.