Don't try Multi Head Configurations with KDE 4.1

There are several issues up to KDE 4.1 in multiple display configurations, so I can not recommend using KDE 4 for that purpose (yet).

See these bugs for more:
https://bugs.kde.org/show_bug.cgi?id=163057
https://bugs.kde.org/show_bug.cgi?id=162623
https://bugs.kde.org/show_bug.cgi?id=158850