.Net核心标签助手智能感知和颜色编码不工作

I am having issues with .NET core and tag helpers. The color coding and the intellisense are not displaying or being registered when I type in asp-for. I've tried creating a new solution in a separate instance, verified that the intellisense works, and then copied the project.json into the project that doesn't have working intellisense/color coding, and it doesn't fix the issue.I am having issues with .NET core and tag helpe