Dell UP3214Q Monitor - Manual (Page 69)

Setting Up Your Monitor Display  69
(d) Setting Display Styles For Multiple Monitor
After the external monitor(s) have been set up, users can select the desired
display style from Multiple displays menu: Duplicate, Extend, Show Desktop
On.
NOTE: Please optimize the size of the icons and fonts on multiple monitors
to suit the user preference.
„ Duplicate these displays: Duplicate the same screen on two monitors
with the same resolution, chosen based on the monitor with a lower
resolution.
(i) For Windows Vista®
[DUPLICATE NOT AVAILABLE]
(ii) For Windows® 7