--removing connections on xwindowinterface destructor
--removing connections on dockview destructor
--remove xwindowinterface that was created from
visibilitymanager in its destructor
--expose quit action
--hide remove action when only one dock exists
--udpate edges when a new dock is added
--connect the destroyed event of containment in order
to remove also the dockview
--remove correctly the dockviews in the application
exit