Was this always the case?
Quote"This event is triggered when the specified item is about to expand or collapse. Label is the expanding or collapsing item's label. Key identifies the item; it is a string if the control uses string keys; otherwise it is a unique handle that identifies the item."
I was banging my head against the wall trying to figure out why my "OnItemExpanding" event kept firing twice. Now I know it's because of the collapse.
Yes, I believe that was always the case. I thought about renaming it "ItemExpandingCollapsing", but that's a mouthful. Anyway, it is now properly documented.