Hello, while now syntactically correct I was not able to solve my logical problem, which is: Stripping a set of keywords of type 'lines' from whitespace and removing blank lines. The properties.dtml method calls 'manage_editProperties:method'. So I searched $(ZOPE_HOME)/lib/python/OFS/PropertyManager.py for this method. This calls 'self._updateProperty(name, value)' and so I've thought it would be sane to override this method with my own. I just copyed the method _updateProperty from and tried def _updateProperty(self, id, value): # Update the value of an existing property. If value # Code was stolen from: /usr/lib/zope/lib/python/OFS/PropertyManager.py # is a string, an attempt will be made to convert # the value to the type of the existing property. self._wrapperCheck(value) if not self.hasProperty(id): raise 'Bad Request', 'The property %s does not exist' % id if type(value)==type(''): proptype=self.getPropertyType(id) or 'string' if type_converters.has_key(proptype): value=type_converters[proptype](value) if id == 'keywords' : # + save_keywords=self.keywords # + self.keywords=[] # + for keyword in save_keywords: # + keyword=keyword.strip() # + if keyword != '' : # + self.keywords.append(keyword) # + else: self._setPropValue(id, value) Unfortunately I see no effect for my changed keyword values. Did I something wrong? Any suggestion how to debug this code? Kind regards Andreas.