Polycom Support
ESU 13 Polycom Support Systems:
Changing Polycom Display Layout - The display button on an HDX system may provide some additional layout control options providing that "dual emulation" option is turned on. To turn on dual emulation follow these steps:
Select "System"
Admin Settings
Monitors
Enable "Dual Emulation" (Dual emulation did not always come with older machines as you had to purchase separately)