I must be losing it! I am currently using PCLinuxOS on different machines and am now trying to on a virtual guest of one of those machines. What I am trying to do is to configure the guest desktop appearance to match the others.

There are two parts to this. One is to remove the transparent 'plasmas' sitting on the desktop. The second is to replace or change the task bar so that it extends to the full width of the screen and is also transparent.
What annoys me is that I have done this before but cannot repeat the steps!

1) you need to change the theme to a non-transparent one systemsettings -> workspace appearance -> desktop theme -> both PerlaNegra & Aya are not transparent (you can get additional ones with the get new themes button)

the theme used is in ~/.kde4/share/config/plasmarc or ~/.kde/share/config/plasmarc depending on distro


2) right click the cashew on the panel (right edge) -> more settings -> maximize panel

sorry maybe I mistook you 1st issue - do you want to change to a non-transparent theme or to remove plasmoids?

to remove plasmoids (widgets) make sure widgets are not locked (right click on desktop -> unlock widgets) then right click the plasmoid -> remove this name-of-plasmoid

Thank you for the concil.
But if we do not know where is plasmoïd and if we do not manage to reach it? ( If we cannot see plasmoïd)
How can it be done?

Merci pour le conseil.
Mais si on ne sait pas où sont les plasmoïd et si on n'arrive pas à y accéder ? (si on ne peut pas voir les plasmoïd)
Comment faire ?

Trouvé cette réponse qui ne fonctionne pas avec Fedora 20 :
(pour enlever tous les plasmoïds)

rm /home/mon-user/.kde/share/config/plasmarc
rm /home/mon-user/.kde/share/config/plasma-desktoprc