model view - variable highlighted for no reason

[AndrewPF]

One of my tables in model view has a "highlighted" variable: 

and I can't think of a reason for it, or what it means. 

It's only this variable which is affected, and only in this table. 

I have even tried removing the column and replacing it and, each time, it comes back highlighted, with no intervention from myself.  
It doesn't appear to be affecting anything else, but I would still like to know what's going on. 

[Mohsin_Zaheer]

This has also happened to me. Not able to find any relationships either effecting this one. Any one can support to resolve this issue?

[AndrewPF]

I don't think that's the case. 

If I select "Group 2" in "Data", I can see that highlighted: 

but "Domain" continues to be highlighted, despite not being selected. 
There are no joins or relationships to or from the table. 

NB/ the highlighting is different in the two variables - "Group 2" has a grey background, "Domain" has a grey background with a black border. 

[audreygerred]

It just means that that field is selected. For example, if I click Calendar DatePreviousYear in the data pane of Power BI, it highlights that same field in the model view:

Similarly, if you are hovered on a join, the field that the join uses will be highlighted: