Reference: Security Program Rights Menu
This selection controls the manner in which the Reset right is assigned. Normally, resetting the rights for a particular drive or directory affects only the one entry being clicked. Any assigned rights are removed, and the entry takes on the rights of its parent. When propagation is selected, all items in the tree below the selected item are also reset. This allows you to quickly “clean out” a particular drive or directory.
Warning: This specific action cannot be undone. You must discard all changes made to this point to recover the information.