I have a strange issue that although not critical I'm wondering why it's happening.
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.
<InstallExecuteSequence>
<Custom Action="CA_SSLCertGenerateInstall" After="WriteRegistryValues">
<![CDATA[NOT REMOVE]]>
</Custom>
</InstallExecuteSequence>
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.
When looking at the schema docs (http://wix.sourceforge.net/manual-wix3/wix_xsd_fragment.htm) InstallExecuteSequence is clearly a valid child of Fragment.