'form' property under schema composition

Hello,

I am confused about the expected behavior of the 'form' property for elements and for attributes under schema composition operations.

How should the 'form' property of elements and of attributes (top level and internal) be affected upon schema composition operations (xsd:include, xsd:import and xsd:redefine) when targetNamespace is (or isn't) defined in the included/imported document and a targetNamespace is defined in the including/importing document?

Are they supposed to maintain their 'form' property? Should they take the 'form' property induced by the importing/including document? Does the expected behavior change if elementFormDefault/attributeFormDefault is defined in the importing/including document or in the imported/included document (or both)? Does it matter whether or not 'form' property is explicitly listed for an element/attribute in these cases?

While I think that the following is clear, I am not clear about the remaining cases:
1. top level names in a schema document with no target namespace are unqualified
2. top level names in a schema document with a target namespaces are qualified
3. top level names in a schema document with no target namespace that are included/imported into a schema document that has a target namespace are qualified

Is that true?

What is the expected behavior in all the cases that are not one of the above listed 3 cases?

Thanks.

Shlomo