Strange pop-up window when opening Firefox.

Cyborganism@lemmy.ca to Firefox@lemmy.ml – 14 points –

Very recently I started noticing something weird every time I launched Firefox. Whether it's a normal session or private session it always happens. When I launch the application there is a small pop-up window that appears with squares of colors, like primary colors, blue, red, yellow. It appears for a fraction of a second. Has anyone else noticed this?

4

I'd guess it's one of your extensions. Try disable all of them and see if it still happens.

Additionally, OP could probably stand to (re)run Malwarebytes.