Collapses a given item.
Original signature is '- (void)collapseItem:(id)item'
Available in Mac OS X v10.0 and later.


- item (Id)
- An item in the receiver.

- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)