When I start
pop
on my Linux desktop a small square appears in the middle of the screen. This square window seems to be originally totally transparent, but has an applied shadow due to my picom configuration, which is as follows:
shadow = true;
shadow-exclude = [
"! name~=''",
"class_g = 'Conky'"
]
inactive-dim = 0.1;
mark-ovredir-focused = true;
Otherwise my system uses X11, i3wm-gaps, picom on the Arch Linux distribution.