NSManagedObject data only shows up in view sometimes

FROM : Adam Gerson
DATE : Wed Apr 02 06:42:19 2008

I have a classic NSTreeController / NSOutlineView situation. The
TreeController has a SortDescriptor on it. I am programatically adding
a leaf node to a group node. It does not appear in the OutlineView
when I first add it. When I inspect the CoreData .xml file the leaf
node is there and it appears to have the right relationships. Then if
I launch the program again there is a 50/50 chance the leaf node will
appear. I just keep launching and quitting the program without making
any changes to the data. Sometimes the child is is the OutlineView and
sometimes it is not.

With a SortDescriptor applied what other changes could cause the
OutlineView to sometimes show a node and sometimes not on different
launches?

Thanks,
Adam