title: InstallExecuteSequence in Fragment not included in installer
body: <p>I have a strange issue that although not critical I'm wondering why it's happening.</p>
  
  <p>After finishing my fairly complex installer I decided to refactor the code and abstract the different tasks into separate fragments. I have C# CustomAction that is being called after the WriteRegistryValues action.</p>
  
  <pre><code>&lt;InstallExecuteSequence&gt;
      &lt;Custom Action="CA_SSLCertGenerateInstall" After="WriteRegistryValues"&gt;
          &lt;![CDATA[NOT REMOVE]]&gt;
      &lt;/Custom&gt;
  &lt;/InstallExecuteSequence&gt;
  </code></pre>
  
  <p>However when I move the above snippet from the Product.wxs into the Fragment, the dll is not included into the installer and obviously the CustomAction is not called.</p>
  
  <p>When looking at the schema docs (<a href="http://wix.sourceforge.net/manual-wix3/wix_xsd_fragment.htm" rel="noreferrer">http://wix.sourceforge.net/manual-wix3/wix_xsd_fragment.htm</a>) InstallExecuteSequence is clearly a valid child of Fragment.</p>