I forgot to say that it still doesn't work after copying libgtksuperwin.so, now firefox doesn't complain about that dependency but it still is not shown in about:plugins page. Besides it creates some conflict with flash that causes finally a segmentation fault:
Adobe Flash Player: GTK1.x environments not supported. Exiting now.Adobe Flash Player: GTK1.x environments not supported. Exiting now.Adobe Flash Player: GTK1.x environments not supported. Exiting now.Adobe Flash Player: GTK1.x environments not supported. Exiting now.Adobe Flash Player: GTK1.x environments not supported. Exiting now.Adobe Flash Player: GTK1.x environments not supported. Exiting now.Adobe Flash Player: GTK1.x environments not supported. Exiting now.Segmentation fault. -- Can't install svg viewer plugin for firefox https://bugs.launchpad.net/bugs/270223 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
