Major Description
The current XML (Castor) based PSML PageManager has a nice "feature" in that a PortletWindow/EntityId only is resolved within the current loaded PSML page.
Meaning: it is possible to reuse the same fragment id (which maps back to portletWindow/EntityId) across multiple pages.
This is very useful for certain type of portlets like calendars etc. for which you want to maintain and interact with only on "singleton" entity basis.
However, this is currently impossible to do with the Database PageManager, as there a fragment Id actually is tied uniquely to one specific page.
As result, current XML based PSML portals which make use of this feature cannot switch to database PSML.
To resolve this, the Fragment/PortletWindow/Entity model needs to be enhanced to support a more flexible relationship definition between them, instead of the current hardcoded 1-1-1 relationship.
This also means that the PSML model will need to be enhanced as well, as I think we need to be able to support reusing both PortletWindows and/or Entities (independently) for multiple fragments.
