Steps to reproduce:
-- Take the Java project from the issue #175481 (see the attachment with the label "a Java project containing one WSDL
file and many XSD files")
-- Open PDOSupplier.wsdl 
-- Switch to WSDL tab
-- Select Messages --> PRAPA_IN201306UV02 --> Body (it is the only message, so it should be easy to find)
-- Switch to Properties view
-- Open editor for the "Element or Type" property.
-- The special dialog appears. It shows different available types. The item "By File" --> StackTraceOverflow can look
different from time to time. Most times it is empty but sometimes it shows project's schema files. I attached pictures
with both cases. I suppose the dialog should always show project's schema files. 
-- Even if the schema files are shown, the dialog doesn't point selection to current type of message part. It works well
only if the part has primitive type, string for example.