Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

I'll check next tinme I restart thanx. could be a while - I have firefox open for long periods

I haven't been able to safe mode yet, but current config is

win 7 64 bit Ff 83.0 (64-bit) ublock origin privacy badger sort tabs advanced CookieMaster

(nothing has changed since the last time it was scrolling smoothly - maybe a week ago? - apart from a Ff update)

something that has also changed recenty (altho I haven't consciously checked on any sites other than instagram) is an extension called internet download manager....the small popup download assist graphic, has gone "distorted light colours". sort of like a traditional (?) graphics driver problem, but no other software has changed my end