I've asked the mailing list and the forum but now answer, so thats why I have to
submit an issue.
We have two projects. Both of them using classes which was generated from valid
schema by the xjc compiler. In Project 1 is an abstract element which will be
substituted by other elements from project 2. When I run the application an try
to unmarshal the valid instance file, the netbeans xml validator says it is
valid, I always get an unexpected element exception which says that the element
out of project 2 was not expected. It expected the abstract element from project
1. But as I said, the element from project 2 substitutes the element from
project 1. Either I'm missing something or I've found a bug.