[duckmuck]

I spoke with a Firefox dev, I was told that due to accessibility settings, multithreading with touchscreens wouldn't come until the current Beta build is released to stable. Technically it should already work on the beta build but it doesn't seem to work for me.

[cpeterso]

AFAIK, accessibility support, including touchscreens, should be enabled in Firefox Beta 52 now:

https://wiki.mozilla.org/Electrolysis#Schedule

In the meantime, you can force Firefox to enable multiprocess, even if you have a touchscreen by creating a new about:config pref "browser.tabs.remote.force-enable" = true.