, because you see the background-picture for the blink of an eye.
Then you see (if you can watch it several times) how the application does its redraw upon the picture(background). Sometimes you see it
- while some part (frame) of a window is picture
- while some part of a window is window-background
- while a window already has redrawn 20% or 70% of its contens
It is really fast.
But the decoration of the window is not affected
Not all types of programs seem to be affected. First i did think it is only chromium, but zoom also was hit.