<customHostSpecified> Element (Office Development in Visual Studio)
The customHostSpecified element indicates that this solution is not a stand-alone application. Office solutions contain components that are hosted inside Microsoft Office applications.
The customHostSpecified element is required for Office solutions. This element is in the co.v1 namespace and specifies that this deployment contains a component that will be deployed inside of a custom host, and is not a stand-alone application.
This element is a child of the first <entrypoint> element in the application manifest. There can be no other child elements in that <entrypoint> element or ClickOnce will raise a validation error during installation.
This element has no attributes and no child elements.