Comment 9 for bug 78809

I last saw this recently, though I still can't reproduce it at will. It happens in both GNOME and Xfce.

Recently I also had another bug: the "You are about to view an encrypted page that contains some unencrypted information" alert sometimes appeared on https://webmail.ox.ac.uk, which hadn't triggered such a warning before and according to its technical support shouldn't.

This may be a duplicate of https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/60236; I have not tried any of their suggested workarounds.

I will try -safe-mode next time I see the bug.