After updating to 18.0 noticed lag on hovering bookmarks (as dropdown list). Checked in task manager: hovering bookmarks rises CPU usage to 25%, which is for my core quad exactly 1 core used to 100%. Stopping moving mouse lowering this value to 0%.
Go to Solution.
Try to disable hardware acceleration in Firefox.
No idea what causes this, but I will make a few suggestions to narrow his down.
It would be worth trying working offline, you would then be able to safely disable any security related software.
Disabling hardware acceleration (and restarting Firefox after that) helped.