When I change something in Audio Volume and Keyboard shortcuts pages, the Apply button remains disabled. Reproducible: Always Manjaro Linux with Plasma 5.4
ok, create one for the keyboard problem under: systemsettings -> keyboard please include screenshots of exactly what you changed.
https://youtu.be/juGFWGav51U
A video goes above and beyond. Thanks Marking as confirmed.
It's because all changes are applied instantly. In Plasma 5.7, the Apply button will be hidden there.