Hi,
I've noticed on desktop firefox that there seems to be an issue with certain screen sizes/zoom levels(?) where the little arrow pointing down does not disappear when scrolled to the bottom sometimes
This causes an funny side effect that you cannot click the links/buttons "behind" the element at all.
note the zoom level top right
If I change the zoom level to lower or higher, or change my browser window size this problem does not exist.
Box model from the root element on firefox with the specific resolution. 
The resolution Looks bit funky, this is a HiDPI scaled 4k laptop screen: xrandr --output eDP-1 --primary --mode 3840x2160 --pos 2160x3166 --rotate normal --scale 0.65x0.65 --filter nearest.
