XSD not referring from WSDL in Local File MDS configured in JDeveloper11g

Error: Most of the time, we create our WSDL and refer the XSD from that WSDL.  However we see that the Element structure won't show in in the JDeveloper in the design time. as shown in the below picture.

Solution:  when you look at the WSDL and XSD every thing looks good wherne you can't traceout the error.  But there is a chance that in the XSD, very first line is an empty line and in the second line in your XSD might be present a XML header  as      xml version='1.0' encoding='UTF-8'?> 

Any XML file the should have the this line as th fist line and fist char onwards.  No spaces is allowed.  So take out if there are any errors.

Now you should be able to see the element structure presenting in your assign activity when you expand the element as shwon eblow.

Similarly, if there is a space in the WSDL file then you might see the below error while you are trying to load the WSDL into your project as a pertner reference.  Error is   ( oracle.j2ee.ws.wsdl.LocalizedWSDLException: WSDLException: faultCode=INVALID_WSDL: Invalid XML in document at: oramds:/apps/AsyncErrorHandlerBPEL/AsyncErrorHandlerBPEL.wsdl, line: 2, column: 6: oracle.xml.parser.v2.XMLParseException: PI with the name 'xml' can occur only in the beginning of the document.  )

So the a solution could be checking and taking out if there ane any empty lines before the first XML header line present in the WSDL's  XML  header section.