Certain types of transparent windows show background as the active border color rather than the desktop

[ThatOneCalculator]

The issue

Certain windows with transparency (like Foot) show fine:

While others like Nautilus (& seemingly all other GTK4 apps) and Zed show the color of the border:

System Information

• niri version: niri 0.1.6 (v0.1.6-56-g589e5a6)

• Distro: EndeavourOS x86_64

• GPU: AMD RX 6700XT

• CPU: AMD Ryzen 7 5800X

[YaLTeR]

This is because they don't signal server-side decoration support. You can override it with this window rule: https://github.com/YaLTeR/niri/wiki/Configuration:-Window-Rules#draw-border-with-background

[ThatOneCalculator]

That worked perfectly, thank you! Is there any reason that option isn't enabled by default?

[YaLTeR]

Windows can be arbitrary shape, for example with rounded corners. Some apps keep them during the tiled state. So niri needs the window to explicitly signal that it uses server-side decorations to omit the border background.