I had the same issue. Solved disabling "Always use the cursor keys to navigate within pages" into Firefox Preferences --> Advanced --> General --> Accessibility.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/643166 Title: Blinking Verical grey bar appears on many websites in recent FF releases -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
