[web/views] Fix exception in CWProperty edit form (closes #5087412)
Also add missing help message. The overall display is ugly, but at least
the message is shown.
# -*- coding: utf-8 -*-
# copyright %(year)s %(author)s, all rights reserved.
# contact %(author-web-site)s -- mailto:%(author-email)s
#
%(long-license)s
"""%(distname)s views/forms/actions/components for web ui"""