This is how you share the bash history across mac tmux sessions with fzf.

First, add this stuff to your ~/.bash_profile.

Then, make mac use ~/.bash_history instead of ~/.bash_sessions. Do this by deleting ~/.bash_sessions (save old sessions to another folder just in case) and add the file ~/.bash_sessions_disable.

Finally, modify fzf at the file: /usr/local/Cellar/fzf/0.22.0/shell/key-bindings.bash. There is a function called: __fzf_history__. Change the line
output=$( builtin history -r;