ALT+1 doesnt work

Greetings gentlemen,

Alt+1,2,3,4... that is used to switch between tabs in librewolf does not work. I have used the vanilla firefox for a long time but i am starting to get their fancy changelogs where they promote homosexuals and spyware, so I am out. However, while this fork of firefox seems fine for now, the alt+1 makes it unusable for me. Yes using mouse is hard. Is there a way to fix, this and more importantly why is this even broken?

i am using linux, appimage since the aur version has been broken for over a year (some signature is not valid)