I use a 2020-21 MacBook Pro. I ALSO use four different browsers for different types of things. Recently, ONLY IN FF have I been getting this little annoyance in the upper left-hand corner of the window when I open a new window. In don't get it anywhere else and cannot understand what a 'Cntrl-Click (Mac)' (right-click on that other platform) tells me about it. I WAS able to eliminate a SIMILAR nuisance about some sort of groups. The icon was a little box split into four sections. With both, the screen gets a white haze over it until clicking on the little box. . I have included a screen shot of the box in question. . Thanks in advance... .