Cannot switch virtual desktops on remote machine

[drusher]

Hello, I am a retired AT&T automation/web developer.

I installed UltraVNC Viewer 1.8.2.4 on my laptop (Windows 11 64-bit, 1920x1080 resolution, and the Server is on my Windows 10 64-bit that has a high resolution 3440x1440 display.

I configured the client as follwows:
* Change Server Resolution 1920x1080 (that's as high as the slider goes)
* Extend Main Display
* Show Toolbar
* Auto Scale by 50%
* On the Server machine, the UltraVNC Display Driver is running as a Service

You can download an image of the config from my sync.com server at:
- https://ln5.sync.com/dl/a9bd1b220#nxfis ... 7-xwqjckf9

UltraVNC displays the widescreen perfectly.
- https://ln5.sync.com/dl/4b07434a0#f84te ... f-2eqm6c2a

I wanted to access other virtual desktops. I clicked the monitor icon with target and got a black screen.
The only way out was to close the session and log back in.

I tried the "Use Only virtual displays win 10".
This blacked out the display on the Server PC and I had to power cycle it to reboot.

What is the trick to getting the virtual displays working?

Thank you.