I just updated my 2011 iMac to 10.13.6 and I followed the instructions at
https://support.displaylink.com/know...k-display-on-m in order to setup the displaylink device with this OS. I only get the screen connected to the displaylink to MIRROR and not EXTEND and there is no option of "Use as Separate Display" listed in airplay like it says should be there.
How do I resolve this?