Comment # 2 on bug 1174239 from Klaus Vink Slott

The duplicate seems quite old by now, but if never got implemented I would like
to vote for it now. I just seen a user starting a update from the KDE systray
and continue work (making the update progress bar in the systray collapse)
followed by hitting the Reboot buttom in the KDE notification, as soon as it
was shown.

You cant really blame a noob user for doing as told.