I recently got a notification balloon in Firefox Developer Edition 40.02a asking if I wanted to turn on e10s. I decided to, but discovered that e10s broke many of my frequently visited sites and plugins (which I have reported already). According to https://wiki.mozilla.org/Electrolysis, I should see an option to turn off e10s in my browser preferences page, but there is no checkbox for that. How do I turn off e10s without having to refresh my browser completely?