Hey.

I think this started around ore some versions before FF87:

When I start FF and the previously saved sessions is loaded (i.e. websites),
then (at least some) add-ons seem not to be active yet, while those sites
load.

The best example is, that webext-ublock-origin-firefox doesn't filter ads
for YouTube vides, when that video is loaded with FF being started.

OTOH, no-script seems to work from the beginning - at least there are sites
loaded at FF startup where I can see that scripts are deisabled. I have hoever
not made any bigger checks onto whether this is really always working.


I'm also rather sure, that this has worked in the past.

I only use add-ons from Debian packages, so I cannot say wheter it would work
for those loaded from the web.


Does anyone else see this, too? Or has some feeling whether this is Debian
specific or rather some upstream issue?
If so I could forward it there.


Thanks,
Chris.

I have been experiencing similar problems on a Debian Sid, using Firefox ESR + uBlock origin and uMatrix from Debian repositories.

I am not sure when it started exactly, but I am quite sure that I have been experiencing it at least since the resolution of #954472 (webext-* packaged addons are not loaded in new profiles). That would lead us back to Firefox 76.

Same here, I do not use Firefox extensions from outside of Debian repositories.

* Christoph Anton Mitterer <calestyo@scientia.org>, 2021-12-24, 22:51:

I use uBlock Origin to disable JavaScript, but when I run:

   firefox -no-remote https://jwilk.github.io/js-sensor/

about half of the time it says JavaScript is enabled.

Possibly related upstream bug:
https://bugzilla.mozilla.org/show_bug.cgi?id=1653237
("Extensions fail to intercept requests that happen before the extension
starts up")