Galaxy S8 screen problem

Dial *#0*#, that will get you the service menu.
Check the screen hardware there. If it passes, it's software, if not, it's hardware (screen).
 
I tried them. Everything seems to be ok.
Is it possible that the theme has bugs? Because if I change it the problem disappears.
 
man those are some bad pictures... there is NOTHING in the first one and the second could very well be compression artifacts.

Dots do usually signify a menu of some sort. If you either tap the area or thumb it down does an app window scroll in?