The theme selector needs to be hidden if the os major version is smaller than 22 because if a gtk theme is not availible but selected gtk falls back to adwaita.
Maybe we can create new themes from all the themes in /usr/share/themes/gtk3 and look up the theme_selected_bg color with yaru.dart's functions createYaruLightTheme / createYaruDarkTheme / createMaterialColor
The theme selector needs to be hidden if the os major version is smaller than 22 because if a gtk theme is not availible but selected gtk falls back to adwaita. Maybe we can create new themes from all the themes in /usr/share/themes/gtk3 and look up the theme_selected_bg color with yaru.dart's functions createYaruLightTheme / createYaruDarkTheme / createMaterialColor