Hi Michael,

That XPath expression yields the empty set.

I created these variables:

<xsl:variable name="first-group" select="$groups[1]" />
<xsl:variable name="Foo-row-first-group" select="($first-group?*)/row[Data

I typed the variables as
  array(element(row))*
that is, a sequence of arrays of "row" elements. So don't use the /row
step, the array directly contains row elements with "Data" child elements:
  $first-group?*[Data = 'Foo']