A Boolean value indicating whether the collection view contains drop placeholders or is reordering its items as part of handling a drop.
- iOS 11.0+
- Mac Catalyst 13.0+
- tvOS 11.0+
When the value of this property is
YES, avoid making any significant changes to the collection view. Specifically, do not reload the collection view's data, as doing so deletes all placeholders and recreates items from the data source.