微软顾问给出的解释：
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n Complex type X is defined in Schema A
n Complex type Y which Extended based on complex type X is defined in Schema B
n Schema C import both Schema A and Schema B, and use complex type X to define one of its record
The issue is:
Once import schema B to schema C, there would be an <equivalent> tag under the record of type X, and both structures for type X and type Y are listed following the <equivalent> tag. At the same time, the links created for this node in map would broke.
This is by design behavior of BizTalk schema editor. When we use a complex type X to define a record in a schema, BizTalk schema tree view will display the structures of all types contained in this schema as well as its imported schemas which are extended from complex type X just like the way we saw.
