this pretty much resolves most of the uncertainities:
we now get a set of mutually dependent services, each of which
is aware of each other member's capabilities, but accesses those
only through this partner's API
After quite some pondering, it occured to me that we both
- need some top-level model::Tangible to correspond to the RootMO in the session
- need some Controller to handle globally relevant actions
- need a way to link action invocation to transient interaction state (like focus)
This leads to the introduction of a new top-level controller, which is better
suited to fill that role than the depreacted model-controller or the demoted window-manager
looks like we're in management business here ;-)
we chop off heads, slaughter the holy cows and then install -- a new manager
