Adds layer of colour behind windows

[kerzeld]

If the effect enabled it darkens translucent windows

With the effect enabled:

Without the effect:

[matinlotfali]

I tried to add translucency to windows using the approach below, but I couldn't notice any difference. Are you using another approach?

[kerzeld]

I use klassy as my application style and colors that define an alpha value.
https://github.com/paulmcauley/klassy

I now tried with using the standard breeze application style and window decorations and the window rule you tried and get the same effect.
The window will get more darker when the window effect is enables.

I also use force-blur but i dont think that has something to do with this.
https://github.com/taj-ny/kwin-effects-forceblur

I am also on nixos.