title: I can't see a referenced class of another namespace in C#
body: <p><strong>I have 2 projects:</strong> </p>
  
  <ul>
  <li>ConstrainedScheduleInterfaces</li>
  <li>ConstrainedSchedule   that has a folder (Testing) with my class that need the reference, here's the code:</li>
  </ul>
  
  <p><strong>Tests.cs:</strong></p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  using 
  using NUnit.Framework;
  using Ninject;
  using ConstrainedScheduleInterfaces;
  
  namespace ConstrainedSchedule.Testing
  {
      internal static class Configuration
      {
        ...........
      }
  }
  </code></pre>
  
  <p>I added the reference to the ConstrainedSchedule project, but the <code>using ConstrainedScheduleInterfaces;</code> is marked red as not found.
  Both the project has destination framework set <strong>.NET Framework 4.5</strong>
  Any help? Thanks</p>