title: Unique Particle Attribution error
body: <p><strong>Aim:</strong>
  I am having an existing standard XSD called Schema1.xsd. 
  I want to extend the complexType("tElementWithIDAndName") of Schema1.xsd in complexType("TVDSection") of Schema2.xsd.</p>
  
  <p>When i try to validate the Schema2.xsd in Altova XMLSpy/oXygen xml editor, I am getting the following error:</p>
  
  <p><strong>Error:</strong>
  [Xerces] cos-nonambig: "<a href="http://www.mySchema.com/Generic/1" rel="nofollow noreferrer">http://www.mySchema.com/Generic/1</a>":element1 and WC[##other:"<a href="http://www.mybasic.com/1" rel="nofollow noreferrer">http://www.mybasic.com/1</a>",""] (or elements from their substitution group) violate "Unique Particle Attribution". During validation against this schema, ambiguity would be created for those two particles.</p>
  
  <p>Schema1.xsd:</p>
  
  <pre><code>            &lt;?xml version="1.0" encoding="UTF-8"?&gt;
              &lt;xs:schema xmlns="http://www.mybasic.com/1" 
                         xmlns:xs="http://www.w3.org/2001/XMLSchema" 
                         xmlns:xml="http://www.w3.org/XML/1998/namespace"  
                         targetNamespace="http://www.mybasic.com/1" 
                         elementFormDefault="qualified" 
                         version="0.1"&gt;
  
                  &lt;xs:complexType name="tElementWithIDAndName"&gt;
                      &lt;xs:sequence&gt;
                            &lt;xs:element name="additionalName" type="xs:string" minOccurs="0" maxOccurs="unbounded"/&gt;
                            &lt;xs:any namespace="##other" processContents="strict" minOccurs="0" maxOccurs="unbounded"/&gt;
                      &lt;/xs:sequence&gt;
                      &lt;xs:attribute name="id" type="xs:ID" use="required"/&gt;
                      &lt;xs:attribute name="name" type="xs:string" use="required"/&gt;
                &lt;/xs:complexType&gt;
              &lt;/xs:schema&gt;    
  </code></pre>
  
  <p>Schema2.xsd:</p>
  
  <pre><code>            &lt;?xml version="1.0" encoding="UTF-8"?&gt;
              &lt;xs:schema xmlns="http://www.mySchema.com/Generic/1" 
                         xmlns:xs="http://www.w3.org/2001/XMLSchema"
                         xmlns:myBasic="http://www.mybasic.com/1"
                         targetNamespace="http://www.mySchema.com/Generic/1"
                         elementFormDefault="qualified" version="0.1"&gt;
  
                  &lt;xs:import namespace="http://www.mybasic.com/1" schemaLocation="schema.xsd"/&gt;
  
                  &lt;xs:element name="Element1" type="TVDSection"/&gt;
                  &lt;xs:complexType name="TVDSection"&gt;
                      &lt;xs:complexContent&gt;
                          &lt;xs:extension base="myBasic:tElementWithIDAndName"&gt;
                              &lt;xs:sequence&gt;
                                  &lt;xs:element name="element1" type="xs:string" minOccurs="0" maxOccurs="unbounded"&gt;
                                  &lt;/xs:element&gt;
                              &lt;/xs:sequence&gt;
                          &lt;/xs:extension&gt;
                      &lt;/xs:complexContent&gt;
                  &lt;/xs:complexType&gt;
              &lt;/xs:schema&gt;
  </code></pre>
  
  <p>I don't know where/how this is violating unique particle attribution.
  Please help me to resolve the above issue.</p>