"Auto-switch USB upstream ports..." not an option in DDM 2.3 & U3824DW

I I have a U3824DW monitor, a Latitude 5450 connected to the powered and video USB-C, and a Optiplex 7020 connected by DisplayPort and USB-C.  Display manager is on both systems and the basics work - I can hot key full screen with keyboard, mouse and peripherals switching.  But, there is no "Auto-switch" option on the KVM dialog.

In PBP, there is a wall between the two sides.  And in PIP, I have to switch the screens then switch the keyboard, mouse, and peripherals.

I believe my specs should support auto-switch.  And ideas one why it's not showing up in either system's DDM?