Updating the Dell D6000 firmware to A03 and installing the DisplayLink 5.2.1 Beta 3 drivers worked for me - but updating the firmware was the real fix. It looked like mine was never updated.
Here's a link (
https://downloads.dell.com/FOLDER056..._A03_T8Y8T.exe) to download the firmware installer to anyone else reading this (need to install on Windows, plug the power into the wall and the usb into the computer)