Use Multiple Monitors via Teamviewer, Anydesk etc

Connecting actual monitors just verifies this seems to be a Windows 10 (Pro) issue. If we enter display properties then the second display cannot be seen. You can use either the HDMI or the DP connection with a single monitor but connect to both and only one is used. We have contacted Intel about the issue but they point out that with W10, Windows now handles the graphics as there is no separate Intel Graphics properties anymore. For whatever reason it seems Windows will not 'see' a second monitor. I am wondering if this is an HDCP / EDID issue.

We have not yet contacted Teamviewer about the issue as this provides multi-monitor support normally, but this is the first time we have tried to do this with Win10 Pro and also the first time we have PC's with dual digital display outputs and one of them being a DP.