How regolith check if a secondary monitor connects or disconnects? (feat. polybar)

[ywpkwon]

Hi, I'm using Regolith 2.1 on Ubuntu 22.04, and this is so cool, and I got one question.
Since this is my laptop, I frequently connect/disconnect a secondary monitor. It's cool that regolith automatically detect connection/disconnection and refresh i3xrocks. (as I know, without Regolith, I'd been needed autoranr or something for this...)

I'm testing polybar, and when a secondary monitor connected/disconnected, I need to also run $HOME/.config/polybar/launch.sh but putting exec_always --no-startup-id $HOME/.config/polybar/launch.sh in regolith2/i3/config.d didn't help. (if I force to reload super+shift+r manually then, of course, the command is callend and polybar updates properly). I want to run the launch.sh automatically when a secondary monitor connected/disconnected. Where can I look at?