NSOutlineView autosaving of expanded/collapsed state

FROM : Ralph Manns
DATE : Sat Feb 23 02:58:03 2008

Hi,

is there a solution on Leopard to implement the autosaving of expanded/
collapsed state of an NSOutlineView (bound to Core Data via 
NSTreeController).
I tried to implement outlineview:persistentObjectForItem; and 
outlineView:itemForPersistentObject:. But it doesnt't work, because 
NSTreeNode and NSManagedObject don't encode with NSKeyedArchiver.
Is there something I am missing, or couldn't state autosaving be done 
in Leopard without 'hacks' like in Tiger?

Ralph.