anchor.diff:        ''
           InputDevice "VBoxMouse"
         '';
  -    
  +
       services.xserver.displayManager.sessionCommands =
         ''
           PATH=${makeSearchPath "bin" [ pkgs.gnugrep pkgs.which pkgs.xorg.xorgserver ]}:$PATH \
  
positive.code:     jobs.virtualbox =
        { description = "VirtualBox service";
  
          startOn = "started udev";
  
          exec = "${kernel.virtualboxGuestAdditions}/sbin/VBoxService --foreground";
        };
  
negative.code:         # /dev/vboxuser is necessary for VBoxClient to work.  Maybe we
          # should restrict this to logged-in users.
          KERNEL=="vboxuser",  OWNER="root", GROUP="root", MODE="0666"
  
          # Allow systemd dependencies on vboxguest.
          KERNEL=="vboxguest", TAG+="systemd"
        '';
  
      # Make the ACPI Shutdown command to do the right thing.
      services.acpid.enable = true;
      services.acpid.powerEventCommands = "poweroff";
    };
  