@notingness In Opera, go to Settings > Appearance > Wallpaper, pick "Custom wallpaper," add a picture, tweak the settings, and then click "Apply." Your chosen image will serve as your background.
@kchochev
Good point !
For instance, I founded another bug, when I open the browser and some islands are closed, they have that white point (new tab inside island):
8854de8f-9247-465f-b25b-972c5281de04-image.png