I am not sure but I think that after I installed version 82 of Firefox I've started experiencing some UI problems. On many sites (in some circumstances) on their loaded pages I see 'black rectangles' which mysteriously disappear after some time as like as they previously have shown... It is very strange and annoying. Before version 82 I have no memory to see that before. I don't know what Firefox developers do, but if their job is to decrease user level of satisfaction of using Firefox browser, than they give their best. These randomly appeared black rectangles on different pages make me nervous. They are like some missing part of a page. Like Firefox, on its desire to show site content as soon as possible, doesn't wait to receive all data packages and on later period (when delayed packages arrive) then fill the black rectangles with data and the pages are represented as they should be. My International Internet Connection is around 20 Mbps and my Homeland Internet Connection is around 50 Mbps, so I don't think that Internet Connection is the reason for these black rectangles. I've set Google as my home page and these black rectangles show even on Firefox starting process when Firefox loads Google site. I don't keep sites' cache data. And I am very curious why on earlier versions of Firefox I didn't notice these black rectangles.