Window of Qt5 apps running natively on Wayland is shadowless on Gnome

Hi

I use Arch Linux running Qt 5.12.2 and Gnome 3.32 on Wayland.

Compare the screenshot showing "About" dialog of Kate text editor.

Kate on Xwayland shows shadow, Kate running natively on Wayland does not.

Steps to reproduce

start Gnome Wayland session

install kate text editor

open terminal and run QT_QPA_PLATFORM=wayland-egl kate

click "Help" menu > "About Kate"