ngraham added a comment.
Typically would would bind both to the same backend value and everything would just magically work. However the code in this KCM is terrible, and is quite imperative, without using bindings properly. So you'll have to manually set both anywhere the slider's value is currently set, and read the value of both anywhere the slider's value is read. REPOSITORY R119 Plasma Desktop REVISION DETAIL https://phabricator.kde.org/D29365 To: kurmikon, #vdg, #plasma Cc: ndavis, ngraham, plasma-devel, Orage, LeGast00n, The-Feren-OS-Dev, cblack, jraleigh, zachus, fbampaloukas, ragreen, ZrenBot, himcesjf, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas, apol, ahiemstra, mart
