anchor.diff:  
       ### Show a background image.
       # (but not if we're starting a full desktop environment that does it for us)
  -    ${if sessionType != "kde" then ''
  +    ${if sessionType != "kde" && sessionType != "kde4" then ''
       
         if test -e $HOME/.background-image; then
           ${pkgs.feh}/bin/feh --bg-scale $HOME/.background-image
  
positive.code:       export XDG_CONFIG_DIRS=${pkgs.kdebase}/etc/xdg:${pkgs.kdelibs}/etc/xdg
        export XDG_DATA_DIRS=${pkgs.kdebase}/share
        exec ${pkgs.kdebase}/bin/startkde
  
      '' else ''
  
  
negative.code:     pkgs.kdebase
      xorg.xset # used by startkde, non-essential
    ]
    ++ optional (sessionType == "kde4") [
      xorg.xmessage # so that startkde can show error messages
      pkgs.qt4 # needed for qdbus
      pkgs.kde42.kdelibs
      pkgs.kde42.kdebase
      pkgs.kde42.kdebase_runtime
      pkgs.kde42.kdebase_workspace
      xorg.xset # used by startkde, non-essential
    ]
    ++ optional (videoDriver == "nvidia") [
      kernelPackages.nvidiaDrivers
    ];
  
  
    extraEtc =
      optional (sessionType == "kde" || sessionType == "kde4")
        { source = "${pkgs.xkeyboard_config}/etc/X11/xkb";
          target = "X11/xkb";
        }
  