title: How to add reference in VS 2015/.NET 4.6?
body: <p>Has VS 2015 changed drastically on how references are added? </p>
  
  <p>I am doing a MVC web project.  I wanted to use <code>System.Configuration.ConfigurationManager</code> in my .NET 4.6 application. I went to the the <code>References</code> node and <code>Add Reference...</code> and added System.Configuration 1.0.0.0. Intellisense now was able to automatically provide the properties and methods for ConfigurationManager, eg <code>ConfigurationManager.AppSettings</code>.</p>
  
  <p>However, when I tried to compile, it says </p>
  
  <blockquote>
    <p>CS0234 The type or namespace name 'Configuration' does not exist in the namespace 'System' (are you missing an assembly reference?)</p>
  </blockquote>
  
  <p>How are things done in the new .NET Framework?</p>
  
  <p>When I hover my mouse over the <code>using System.Configuration</code> statement, there's a balloon text with yellow triangle and exclamation mark that says:</p>
  
  <pre><code>{} Namespace System.Configuration
    MyProject.DNX 4.5.1 - Available
    MyProject.DNX Core 5.0 - Not Available
  You can use the navigation bar to switch context.
  </code></pre>
  
  <p>Whatever does this mean?</p>