Identity Safe Icon Appears on Random Pages - Firefox

I activated Identity Safe this morning, and deactivated it (or attempted to) this afternoon, in part because the icon was appearing in random places on websites, over text I was attempting to read. 

This is still happening, despite deactivating it in frustration, and then a system restart.  I'm using Windows 10 and Firefox 49.0.1.

Most recently it popped up in the middle of a "was this site useful" form here on Norton's own site.

This is very frustrating.