Barco CORONIS MFGD 3621 - Manual (Page 104)

General tips
104
Note: If you have a single display configuration and you have
enabled DualView, Windows will not allow you to attach the
second head. This is normal and not a bug.
After enablingDualView and setting the resolutions in a Quad-
Head Configuration you may need to drag the heads into the
proper position in the window on the “Settings” tab, so that the
arrangement in the window on the “Settings” tab matches the
physical arrangement of your configuration.