That is tricky, it's a work computer. If this is a unique issue, not known elsewhere, I will stick with FVD in Chrome...

No it doesn't appear. New tab controls are just the default for Firefox.

Checking back on add-ons, there is no evidence of it being installed. I search again, it shows as available to install, I click Install and am prompted to re-start Firefox. Then it's not there.... repeat...

I use FVD all the time in Chrome.

Thanks for your reply, it's 48.0