The expand status indicates whether dependent items are visible or not. A parent item that has one or more visible dependents is considered expanded. If a parent item is expanded, all its immediate dependents, i.e., all dependents on the next lower level are visible. If a parent item is collapsed, no immediate dependents are visible.
The Item.Expanded property can be used to determine the current expand status of an item.
Items can be expanded and collapsed using the Item.Expand and Item.Collapse methods.
An item can be marked expandable using the Item.Expandable property, even if it has no child items.