question: private void unregister ( final CGraphWindow window ) { if ( ! m_graphs . remove ( window ) ) { throw new IllegalStateException ( "IE01206: Graph window wasn't registered" ) ; } for ( final IWindowManagerListener listener : m_listeners ) { try { listener . windowClosed ( this , window ) ; } catch ( final Exception e ) { CUtilityFunctions . logException ( e ) ; NaviLogger . severe ( "Internal Error: Listener caused an unknown exception" ) ; } } }
target:  Unregisters a graph window when it is closed.