VSCode (Electron?) not respecting Gnome Dark/Light theme

For some reason electron based apps such as VSCode and Discord don’t respect Gnome’s Light/Dark theme. On Debian those apps adapted easily to Gnome’s current variant.

Any ideas what’s the problem why this isn’t working on NixOS?

Hm the issue is not only with electron based apps but also with Gnome Terminal… what does NixOS so differently to Debian that this does not work?