Greasy Fork

Wonderful script. Works great when it works.
From time to time it will randomly disappear from my TamperMonkey scripts list, and thus won't be working... but when I search for it every time on GreasyFork and go to the script page, the button says "Reinstall" (and not "Install") this script... clicking on reinstall and then refreshing WhatsAppWeb gets it working again, but this is an odd behavior.
I have attempter Reinstalling, then UNinstalling it, then restarting (the whole PC), then Installing the script again, but it didn't work in the long-run.
Any idea what could be causing this and how to permanently resolve it?

I am sad to report it is not working anymore. I thought at first it was just clashing with WhatsApp Hide Chat List, but I have tried and it happens when used alongside any other script (that I have, at least). Sometimes it doesn't happen, most of the time it does. I can't tell what makes it happen... seems random somehow. So for now, it's unusable unless this is the only script I want to use for WhatsApp Web, which it is not.