Easy to reproduce. Add a reference to the MVC futures assembly to your MVC project and the appropriate using:
Try accessing any of the helper extensions such as this one in a cshtml file. This one builds a link with strongly typed controller reference:
Or define your own extension methods for HtmlHelper, etc. in a separate class. JustCode will not resolve these at all. Everything not standard in the HtmlHelper core class will fail/marked as red. Big annoyance in MVC/Razor. Main reason I don't use JC anymore.