Tree is missing "item_expanded" signal

[TX256]

I was surprised to find out that there is no signal for listening the expanding of a tree item. There is item_collapsed, however. I think this should definitely exist. Is there a workaround?

[Anutrix]

I am also looking for the same signal.
My use case is to add child TreeItems dynamically when the parent treeitem is expanded.

[AThousandShips]

This is a documentation issue, the signal is emitted when the collapsed state changes, not only when collapsed

[Calinou]

Pull request opened:

• Document Tree.item_collapsed also being emitted when the item is expanded godot#109242