After I installed Win 10 Pro upgrade 1903, DisplayFusion quit working. On my Surface Pro v4, I can't find my active external HDMI monitor. When I go into Win, I can select and configure the external HDMI monitor.
NOTE: I am using the external monitor INSTEAD of the Surface Pro v4 monitor.

An error has occurred while applying your new Monitor configuration.
Please check your settings and try again.
Error: Failed to call SetDisplayConfig. [HR: 87]