I've accidenately hit quit button and it closed all my 7 sessions with processes running!!!!!!! I've "confirm blabla if multiple sessions" tick on, but it doesn't work KDE Plasma Version: 5.12 OS KUBUNTU 18.04
It should be fixed with https://phabricator.kde.org/D15535 but its currently being reviewed.
*** This bug has been marked as a duplicate of bug 398776 ***