clear vreg's parent_classes cache to fix etype cache / auto-reloading bug EtypeRegistry.parent_classes()'s is cached. When the registry is reloaded, if the cache is not cleared, we might get the old list of parent classes and that leads to strange bugs. Typical scenario : 1/ start application in debug mode 2/ go to add/Bookmark -> everything's fine 3/ change the source 4/ reload add/Bookmark -> 'creation' not selectable because : a/ cw detects a change in the source and reloads vreg b/ cw tries to select 'creation' view for 'Bookmark' - 'creation' view uses specified_etype_implements('Any') - cw compares Bookmark.__bases__[0] (i.e. new version of AnyEntity) with the old version of AnyEntity cached in the vreg. They don't match => view is not applicable.

"""cube-specific forms/views/actions/components

:organization: Logilab
:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""