[Zope] Is Zope syntax inconsistent ?

I've hit the 'Zope Wall' again ! Can anyone explain why <dtml-if expr="AUTHENTICATED_USER=='zope'"> ZOPE ! <dtml-else> NOT ZOPE ! </dtml-if> <dtml-var AUTHENTICATED_USER> <br> Displays NOT ZOPE ! zope While this <dtml-if expr="tune_id=='Reel'"> REEL ! <dtml-else> NOT REEL ! </dtml-if> <dtml-var tune_id> Displays REEL ! reel Which is what I expected ! Richard Moon richard@dcs.co.uk