Hello! Please help me. I'm using the latest version of regular Opera, not GX. In full-screen mode (watching videos in full-screen mode or pressing f11), white triangles appear at the corners of the screen. It only appears in Opera. What is it and how to remove it? You can see it in the screenshot, but on a dark background. Here I just opened the picture in opera in full-screen mode.
Triangles in fullscreen mod