[Zope] Detecting Roles not working

[Jonathan Cheyne]

Hi all

I have built the basis of a site with full, form-based webediting of
objects. Coming round to cleanup time and I wanted to remove certain
visible functions from the default object views unless you have already
logged in (with various possible roles)

in the index_html of my zclass i have

<dtml-if "AUTHENTICATED_USER.has_role('Staff')">
<a href="<dtml-var absolute_url>/<dtml-var type>edit">edit this</a><hr>
</dtml-if>

so if the user is anonymous or logged in without the Staff role assigned
they should not see the "edit this" link ...

Doesn't work! It basically never returns a 'true' response thus never
displays the edit this link even when logged in.

Tried various permutations and variations on this theme without any
success.

Help! Without this, I am not sure how to customize the interface for
different user groups.

I am on 2.2.0 but I think it was similar under 2.1.6.

Absolutely any clues no matter how obscure would be gratefully received
(or indeed the glaringly obvious solution etc :-)

Cheers

Jonathan