When I arrived at the office I noticed that the taskbar is missing in my KDE4 Fedora workstation. Good thing is that I have a KDE konsole application still left running. I didn’t realize early that the solution to revive the taskbar was that easy.
First thing I do was to launch Firefox from terminal then searched for possible solution. The solution was just to run this on terminal.
That’s it! XFCE has same weird problem as well and you just have to run similar application (different name though) to bring back the taskbar or panel.