Comment # 5 on bug 1095198 from Andreas Nordal

Sorry, the problem went away when I factory reset Firefox
(https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings).

I have no idea why �����I'm not using any plugins or addons or settings that I'm
aware of.

My colleague (using Ubuntu) also upgraded to Firefox 60.0.1 and had no
problems.