Posted before an item is expanded (after the user clicks the arrow but before the item is collapsed).
The notification object is the outline view that contains an item about to be expanded. The userInfo dictionary contains the following information:
KeyValue@"NSObject"The item that is to be expanded (an id)
Available in Mac OS X v10.0 and later.
Declaration Syntax Version Information- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)