I have three monitors, 2 utilize onboard video, while the third is via a USB DisplayLink Adapter. When I check the settings in the Horizon Client, I can see all three monitors and they can be checked. However, when I go back to the remote desktop the maximum I can get is two monitors, the ones utilizing the onboard video. Is there an issue utilizing USB DisplayLink adapters?
I performed a test in the client, changing the settings to 2 monitors, selecting the onboard video and the USB DisplayLink Adapter video, and that worked fine, so I effectively ruled out issues with the USB DisplayLink adapter.
Maybe a stupid question, but is your desktop pool enabled for 3 monitors? Check the desktop pool settings in the Horizon Console to check what the maximum number of monitors and resolution is for the desktop pool.
When I check 3 monitors in the desktop pool, the desktop will momentarily expand to 3 monitors but it is effectively split to 1/2 screen on monitor 1, full screen on monitor 2 and half screen on monitor 3. It then quickly reverts itself to 1 monitor