Options that aren't supported by KDE Neon should be greyed-out. Muon Version 5.6.0 KDE Neon 5.7 (user edition) Reproducible: Always Steps to Reproduce: 1. Open Settings -> Configure Software sources 2. Go to the Updates tab Actual Results: - There's a checkbox area at the top for "neon updates", but clicking on them instantly reverts the check mar. Those boxes should be greyed-out if there's no intention to support them. - It's possible to change "Long-term support releases" to "Normal releases". Since KDE Neon is based officially only on LTS relases, that may break things when new Ubuntu releases are launched. That option should be greyed-out.
software-properties-kde is not part of muon (and neither of kde). It is an external application which is invoked to configure software sources. Development is at https://launchpad.net/software-properties/trunk Reassigning to neon, maybe it makes sense to fix it with a patch in packaging ?
Low priority for us, Discover is our main package UI, Muon and software-properties are not well supported.