For example the image below shows an NSOutlineView bound to a tree structure based on folders and items using an NSTreeController:
What I want is the Item objects to remain in the model, but not to be displayed as rows, i.e:
The NSOutlineView delegate protocol has a method that informs the delegate that an item is about to be displayed, but doesn't give the option not to display it.
Is there some way in which to subclass NSOutlineView to implement this (or some other method)?
Thanks.