If Current Node Is Ancestor!

Hi all,

I am trying to test whether a current node is an ancestor of a menu node
with a dept attribute equal to $depth. I appear to be struggling with this
conceptually and would appreciate any help!!

<xsl:if test="//menu[@dept != $dept]/ancestor::menu ">
  <xsl:attribute name="class">nav_close</xsl:attribute>
</xsl:if>

Cheers,
Adam