An xsl:choose with a single xsl:when and no xsl:otherwise says what an
xsl:if says, and sends its reader looking for a second branch that is not
there. Write the xsl:if. A choose that also has an xsl:otherwise is a
genuine if/else and is left alone, and a choose with no xsl:when at all is
reported by empty-choose, not here.
Incorrect:
<xsl:choose>
<xsl:when test="@active">Active</xsl:when>
</xsl:choose>
Correct:
<xsl:if test="@active">Active</xsl:if>