Hi Michael,

One question about nilled element:
1. schema file

<?xml version="1.0" encoding="utf-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:eg="http://xbrl.org/formula/conformance/example" xmlns:formula="http://xbrl.org/2008/formula" xmlns:variable="http://xbrl.org/2008/variable" xmlns:label="http://xbrl.org/2008/label" targetNamespace="http://xbrl.org/formula/conformance/example" elementFormDefault="qualified" attributeFormDefault="unqualified">
  <import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <element id="c1" name="c1" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" />
  <element id="n1" name="n1" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" />
  <element id="n2" name="n2" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" />
  <element id="n3" name="n3" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" />
  <element id="b1" name="b1" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" />
  <element id="d1" name="d1" type="xbrli:dateTimeItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" />
</schema>

2. xml file:

<?xml version="1.0" encoding="UTF-8"?>
<!-- Copyright 2007 XBRL International. All Rights Reserved. -->
<xbrl
xmlns="http://www.xbrl.org/2003/instance"
xmlns:concept="http://xbrl.org/formula/conformance/example"
xmlns:link="http://www.xbrl.org/2003/linkbase"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:iso4217="http://www.xbrl.org/2003/iso4217"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>
 
  <link:schemaRef
    xlink:type="simple"
    xlink:href="22010-xpathUsage-tests.xsd"/>

  <link:linkbaseRef
    xlink:type="simple"
    xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"
    xlink:href="22010-xpath-dynamic-type-safe-formula.xml"/>
 
  <context id="context">
    <entity>
      <identifier scheme="http://xbrl.org/entity/identification/scheme">01</identifier>
    </entity>
    <period>
      <instant>2007-12-31</instant>
    </period>
  </context>
 
  <concept:d1 contextRef="context" xsi:nil="true"/>
 
</xbrl>


3. xpath expression:
//*[. instance of schema-element(xbrli:item) or . instance of schema-element(xbrli:tuple)]

returns empty sequence instead of the nilled element
<concept:d1 contextRef="context" xsi:nil="true"/>

Do you have any suggestions?

Thanks and best regards
Malix