Digital Override Display question

Hello!

I have MacMini (Late2014) running El Capitan (10.11.2) and either Wacom Cintiq or Dell display attached to it via HDMI (only one display at a time). But when I look up Displays preferences, this is what I see:

Basically, I seem to have some sort of "ghost" display present there at all times.

The question is how do I get rid of this? If this might be important, I had logic board replaced because of factory defect of the original one.

Thank you!