Eclipse IDE does not fill elements and attributes in sample XML file

I'm trying to generate XML file starting from a DTD schema for testing purpose. I've read different solution but this one seems to be the simpler and for sure free. The problem is the tool correctly generate the XML file but "forget" to fill the elements and attributes with data so to be quite useless.

There is a particular reason for this behavior? There is a sort of fix?

setting up

result