I tested the Orchis theme and it looks good, I think: ![geany_windows_orchis](https://github.com/geany/geany/assets/617017/0a43ca17-41f1-45e3-b9f3-682f740...)
Since you said you installed the theme into `AppData/Local/gtk-3.0`, this might cause the problems. Usually, themes are to be put into `AppData/Local/themes` and then configured in `AppData/Local/gtk-3.0/settings.ini`, e.g.: ```ini [Settings] gtk-theme-name=Orchis gtk-application-prefer-dark-theme=1 ```
This worked for me. See also https://www.geany.org/documentation/faq/#on-windows_1.
Feel free to re-open if I'm wrong.