XML not validating against XSD

Question

Given the following representative snippet:

<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:j="http://foo" xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://foo" elementFormDefault="qualified" attributeFormDefault="unqualified" version="3.2">
<xs:element name="Event">
    <xs:annotation>
        <xs:documentation>The Incident beginning and end date and time</xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:complexContent>
            <xs:extension base="j:EventType"/>
        </xs:complexContent>
    </xs:complexType>
</xs:element>
<xs:complexType name="EventType">
    <xs:sequence>
        <xs:element ref="j:EventDate" minOccurs="0"/>
        <xs:element ref="j:EventTime" minOccurs="0"/>
    </xs:sequence>
    <xs:attribute ref="j:EventType" use="required"/>
</xs:complexType>
<xs:attribute name="EventType">
    <xs:simpleType>
        <xs:restriction base="xs:string">
            <xs:enumeration value="Beginning"/>
            <xs:enumeration value="Ending"/>
        </xs:restriction>
    </xs:simpleType>
</xs:attribute>

The following XML doesn't validate. Specifically, it won't validate the EventType attribute.

<?xml version="1.0" encoding="utf-8"?>
<SomeDoc xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://hostedbykarpel.com/Schemas/ReferralDocument_2">
  <Event EventType="TypeOne">
    <EventDate>2013-12-18</EventDate>
    <EventTime>00:15:28</EventTime>
  </Event>
</SomDoc>

However, if I explicitly add the namespace inside the element it works:

<Event a:EventType="TypeOne" xmlns:a="http://foo">
  <EventDate>2013-12-18</EventDate>
  <EventTime>00:15:28</EventTime>
</Event>

The namespace is already declared at the root of the document. Why would I need to specify it again just to get the attribute to show up? The Event element itself validates just fine, it's just the EventType attribute that won't.

Answer 1

I think this behavior is defined by spec for named attributes referenced with ref. I don't believe there's a way to change it. However, you could get around by not using ref.

<xs:complexType name="EventElement">
  ...
  <xs:attribute name="EventType" type="j:EventTypeValue" use="required"/>
  ...
</xs:complexType>
...
<xs:simpleType name="EventTypeValue">
  ...
</xs:simpleType>