It happens with all applets. If you click on application launcher and click on show desktop or in the workspace applets, the application launcher also disappears too.
I think it occurs with all applets.
KDE 4.2.4 isn't robust enough for this kind of use, yet.
That was the reason I said in another thread that KDE likes gently users.
http://www.linuxquestions.org/questi...ers...-743743/
Anyone could report the bug?