VBA in Word- color change

[Field8]

Hi guys, I know this forum is about Excel, but I have a Word question- same language. I'm creating an HR form, and I'm using Content Controls in the Developer tab (not the legacy tools). For all the other content controls, the field is grey, and then turns black when a response is selected, or when a field is filled in. But not with the drop-down menus. They stay grey. I'm trying to figure out how to get them to turn black when the user selects something. (I'm actually using the "combo box", which is a drop-down menu with editing capabilities). Does anyone know how I'd go about writing code for this?

Thanks!