title: App.Config returns null
body: <p>I have a class library project in which I want to load configuration settings.  </p>
  
  <p>Here is the app.config file.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8" ?&gt;
  &lt;configuration&gt;
    &lt;appSettings&gt;
      &lt;add key="editMode" value="2" /&gt;
      &lt;add key="fileType" value="0" /&gt;
      &lt;add key="Editor" value="C:\Program Files\Adobe\Adobe Photoshop CC 2015\Photoshop.exe" /&gt;
    &lt;/appSettings&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Here is the code inside of the main program.</p>
  
  <pre><code>string savedEditor = ConfigurationManager.AppSettings["Editor"];
  MessageBox.Show(savedEditor);
  string savededitMode = ConfigurationManager.AppSettings["editMode"];
  MessageBox.Show(savededitMode);                
  string savedfileType = ConfigurationManager.AppSettings["fileType"];
  MessageBox.Show(savedfileType);
  </code></pre>
  
  <p>It compiles OK and the <code>*.dll.config</code> file is created.  However, it returns null for the values of the three keys.  What am I doing wrong?  Thanks.</p>