add: setDisplaySubitemsAsGroup( true ); if ( listView () ) listView ()->setRootIsDecorated( false );
context:     FreeBusyItem( Attendee *attendee, KDGanttView *parent ) :      KDGanttViewTaskItem( parent ), mAttendee( attendee )    {      Q_ASSERT( attendee );      updateItem();      setFreeBusyPeriods( 0 );    }