Populating / prefilling a form field by URL Query String does not work

When I create or edit content I cannot use a query-string to populate the form fields.

E.g. demo.plone.org has no effekt and the title field remains empty. This used to work in older versions and I don't know when and why it stopped.

collective.easyform does not have this behavior even though it is also based on z3c.form.

It changed in Products.PloneHotfix20160830 version 1.3 -- see Security patch has been released: 20160830 - #7 by mauritsvanrees

There is now an attribute allow_prefill_from_GET_request which can be set to True to still allow this (default: False). easyform does this explicitly: collective.easyform/view.py at master · collective/collective.easyform · GitHub