[Zope] Help with simple dtml-if compare

Bug? Or am I missing something. Create a default document called 'index_html', with these contents: <dtml-var standard_html_header> <dtml-if "id == 'index_html'"> index_html == <dtml-var id> <dtml-else> index_html != <dtml-var id> </dtml-if> <dtml-var standard_html_footer> Basically, we're comparing the document id -- "index_html" to the string "index_html". If you run it, the results say: index_html != index_html Why is that?? Any help? Ideas? Thanks PK