If you are completely new to KDE 5 for Slackware, I urge you to also read my previous posts about KDE 5_15.01 and KDE 5_15.02 in its entirety, as well as the follow-up article about the changes in system tray support in the Plasma 5 desktop which is mandatory reading material as well if you are using Dropbox, Skype and other non-Plasma 5 software that wants to dock an icon in the system tray.