Hey @christiansakai, thanks for the kinds words!
By default, in a shell with readline support, C-s is already bound to an action, specifically forward-incremental-history-search (the oposite of C-r).
Since we configure tmux to use C-s, we lose the ability to do forward-incremental-history-search. The configuration I demonstrate allows us to get the behavior back by pressing C-s twice.
Hope that helps, but please let me know if you have any additional questions.