A lucky find!
FYI - my other USB devices on the Asus Z270 type mobo are:
Steinberg eLicenser dongle
Logitech wireless mouse dongle
Acer multitouch display control
Steinberg UR824
… and now, the 4-Port, USB 2.0 hub with the Steinberg Midex8 connected.
It appears that, originally, the Midex driver installation did not fully install in Windows 10 until the USB hub was introduced. During the first time the Midex was plugged into the USB jack, no installation wizard popped up as in the documentation. I don’t know if this normally happens in Windows 10. I just ran the latest driver .EXE file after connecting the Midex, and the system started acting weird. Windows hung up at a Black Screen during shutdown or restart until unplugging the Midex. Another weird behavior when the Midex was plugged in to the PC’s USB, Windows Remote Desktop Protocol stopped functioning. I frequently control this PC remotely from an iPad. These kind of problems can be challenging. Now Windows RDP works again, and Midex8 works.