Version: (using KDE 4.3.4) OS: Linux Installed from: Debian stable Packages The wallpaper on the desktop shows through the panel, and there does not seem to be any way to make the panel opaque. The result is that the names of the virtual desktops are very difficult to read. Disabling "desktop effects" does not help. There does not seem to be any advantage, aesthetic or otherwise, to having the wallpaper show through the panel.
Panel transparency currently depends on the plasma theme.
See above comment.