I don't know what it is, but here's an idea. In the VS search (see my other reply), type in highlight. One of those items may be what you want.
>Anyone would know how to turn that one off?
>
>See image.
>
>This is like that with the new Visual Studio 2015. There are no errors in the code and that keeps like that.
Craig Berntson
MCSD, Microsoft .Net MVP, Grape City Community Influencer