Version:            (using KDE 4.3.1)
OS:                Linux
Installed from:    Debian testing/unstable Packages

When you use a spacer in the panel to tame expanding widgets like the taskbar and the activity switcher it isn't possible anymore to access the configuration menu of the taskbar because for accessing it you have to rightclick on an emtpy space in the taskbar. With a spacer there is no empty space at the end of the taskbar. So either there always should be a little space left at the end of the taskbar (a few pixel is enough) to allow to access its context menu or the context menu of the taskbar should also be available when rightclicking on an entry in the taskbar.