I've understood what the problem is. It's a bug of an extension: tab mix plus 0.3.7.3 After uninstalling firefox works fine.
Thanks, Dome -- customizable buttons disappear every firefox start https://bugs.launchpad.net/bugs/300277 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
