Razor HTML Helpers giving intellisense errors in Nop Commerce Plugin

Question

I am writing a plugin for Nop Commerce and my HTML helpers are giving me intellisense errors. I get red lines underlining them and the errors:

Feature \'extension method

Answer 1

The project needs to know its in plugin development

1: Close your solution 2: open your *.csproj file with any editor 3: Add the following near the end of the project closing tag

4: reload the solution/project