@gemlog Firefox broke plugins when they got rid of NSAPI, a 20 year+ old browser plugin API that was (accused of) being a insecure.
Browsers have become a complete graphical operating system and virtual machine with a fat ass memory footprint. "Browsing" means something very different to what it did 10 years ago.
Your choices are: ride the edge (Firefox, Chrome, Exploiter), or depend on the notion that W3C standards are worth a damn and browse with alternates.
I can see you've tried that. :-)