Removing "layout" property — AttributeError: manage_delProperty

In one of our Plone 4 sites, we’re seeing a strange behavior where on some objects that have a “layout” property set (i.e. view selected) the “display” menu disappears and is not rendered at all.

While we try to figure out why this is happening, I wanted to create a script which would site admins to delete that layout property without exposing them to the ZMI.  So, I created a script which looks like this:

= = = = = = = = = 
from Products.CMFCore.utils import getToolByName

plone_utils = getToolByName(context, 'plone_utils')
r = context.REQUEST

obj = context.aq_explicit

if obj.hasProperty('layout'):
   obj.manage_delProperty('layout')
   plone_utils.addPortalMessage(_(u'The layout property has been deleted.'), 'info')
else:
  plone_utils.addPortalMessage(_(u'This object has no layout property.'), 'info')

return r.RESPONSE.redirect(obj.absolute_url())
= = = = = = = = = 

When I run the script I get the following error about "AttributeError: manage_delProperty"

Traceback (innermost last):
  Module ZPublisher.Publish, line 138, in publish
  Module ZPublisher.mapply, line 77, in mapply
  Module ZPublisher.Publish, line 48, in call_object
  Module Shared.DC.Scripts.Bindings, line 322, in __call__
  Module Shared.DC.Scripts.Bindings, line 359, in _bindAndExec
  Module Products.PythonScripts.PythonScript, line 344, in _exec
  Module script, line 10, in resetLayout
   - <PythonScript at /portal/resetLayout used for /portal/data/regional-geo-data/invertebrates>
   - Line 10
AttributeError: manage_delProperty
 
When I debug this, it appears that obj is in fact the object I want, as it has the correct ID and passes the check for having the “layout” property in the first place.

Am I using the correct method, manage_delProperty()?  Any ideas why this would fail?

thanks,
--
David Siedband
http://zentraal.com


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