In my opinion every exit option in kde system setting or maybe every setting should prompt it's user to apply/discard it's change . since what i found is by pressing esc while in keyboard setting, discard any or is this issue only happen to me. im sorry if this is another duplicate issue (tried to search but found nothing similar issue) Thank You :)
Confirmed. Any time the "Apply" button is active, you can navigate away without triggering a confirmation dialog.
I can confirm missing apply/discard dialog when I start user-manager via apps menu (kicker). But I can not confirm when I open user manager via system settings in icon view mode. If you open user manager via system settings in sidebar view maybe this report is duplicate of bug 392160. Furthermore, I noticed that when I open kscreen kcm via kicker I get no apply/dialog when I close the window immediately after to change the screen resolution. So maybe we have a bug that affects several kcms started via apps menu.
(In reply to Dr. Chapatin from comment #2) > But I can not confirm when I open user manager via system settings in icon > view mode. > If you open user manager via system settings in sidebar view maybe this > report is duplicate of bug 392160. I just tested using exit through window close button on system setting. the result is, yes it does prompt to apply, discard or cancel. the escape button wont close / change the setting either. it just stays there. but there are another problem, when i select another setting option it doesn't prompt me to apply,discard, or cancel it just open the new setting option and discard all my changes.
This is fixed in the Plasma 5.20 rewrite.