Hello, could you please elaborate ? What is not working ? Do you have an error in the console ? Are you able to reproduce this issue on a particular website ?

I would be glad to fix it but I need some information :)

Thanks,
Guillaume

Edit: I think it might be related to this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1267027
On Firefox, pages viewed directly from GitHub may not render properly. This is result of a Firefox bug carrying over the restrictive content security policies (CSP) that GitHub sends to content inserted by the WebExtension. Please note that this issue can also occured on other websites with restictive CSP.