[Zope] dtml-if problem

[Tamas Amon]

Hello,
I have a little problem, but I don't find the solution for it. Here is
the code:
-----
<form name='ware'>
<select name="warez" onChange="document.ware.submit()">
<dtml-if warez>
<dtml-in wares>
  <dtml-if expr="id == warez">
     <OPTION VALUE=<dtml-var id> DEFAULT><dtml-var sname>
  <dtml-else>
     <OPTION VALUE=<dtml-var id>><dtml-var sname>
  </dtml-if>
</dtml-in>
<dtml-else>
<dtml-in wares>
     <OPTION VALUE=<dtml-var id>><dtml-var sname>
</dtml-in>
</dtml-if>
</select>
</form>
-----
But the 
<dtml-if expr="id == warez"> is never true. Why it is possible?

Thanks for your help.
-- 
Amon Tamas
sajt@amon.hu