On the debugging of page templates

Try embedding something like this in your code:

<dl class="collapsible inline collapsedOnLoad">
   <dt class="collapsibleHeader">Title</dt>
      <dd class="collapsibleContent">
         <span tal:replace="structure python: here.printRequest(request, errors)"/>
      </dd>
</dl>

and supply the necessary printRequest somewhere in your code or as a script:

def printRequest (self, request, errors):
        req = dict(request)
        buf = StringIO()
        buf.write ("<div>")
        buf.write ("<p><b>request:</b></p>")
        buf.write ("<ul>")
        for k, v in req.iteritems():
                buf.write ("<li>%s: %s</li>" % (k, v))
        buf.write ("</ul>")
        buf.write ("<p><b>errors:</b></p>")
        buf.write ("<ul>")
        for k, v in errors.iteritems():
                buf.write ("<li>%s: %s</li>" % (k, v))
        buf.write ("</ul>")
        buf.write ("</div>")
        return buf.getvalue()