KDocker: Dock Any Application in the System Tray in KDE, GNOME & Xfce

I bet at one point or another you felt you missed the system tray integration feature in some application, be it xterm, an audio player, a file manager or any other program. Well, KDocker is just the thing which comes to help: a simple, yet practical docking application built for KDE4 (older KDE3 version can be found here), but not only. Let me tell you how to use this program in a productive and useful manner.