title: How to add an MSI file to my installer
body: <p>I have WiX 3.6 (Oct 2011) installer for my application. My application requires another service to be installed in the system. I added an MSI file to my installer this way:</p>
  
  <pre><code>&lt;Fragment&gt;
      &lt;PackageGroup Id="MyService" &gt;
          &lt;MsiPackage Id="MyService" Name="MyService" SourceFile="MyService.msi" DisplayInternalUI="yes" EnableFeatureSelection="yes"&gt;
          &lt;/MsiPackage&gt;
      &lt;/PackageGroup&gt;
  &lt;/Fragment&gt;
  &lt;Fragment&gt;
      &lt;ComponentGroup Id="APPFILES"&gt;
      ...
  &lt;/Fragment&gt;
  </code></pre>
  
  <p>The installer works fine, but this additional MSI file is not installing. What am I missing?</p>