Kvantum Layan theme transparency does not work in full screen windows

I have applied the Kvantum Layan theme and for some reason when I have a program on full screen, the transparency for something open on top no longer works. Let me demonstrate:

With both windows being in windowed mode transparency works fine:

But as soon as I make a single window full screen, the transparency for everything goes away (even the start menu):

Any ideas? (also why do some windows just not support transparency like Pamac, do I need to install something else or is there no hope)

Contact the theme developer.

Theming the … out of a system usually causes more trouble than one like.

You are displaying the diffs between a GTK and Qt app. Accept the difference.

Yes I know - theming is a matter of taste - I won’t argue on that.

The best result - long term - personal experience - comes from using the defaults for the platform and use the default theme.

You can use qt5ct and qt6ct to smoothen the differences between gtk and qt. Using kvantum - my personal opinion - is making things more complicated - again - very personal.