Selective undo of editing operations performed on data objects

摘要

An undo process performed on a data object includes selecting a stored prior state of the data object; comparing the stored prior state with the current state of the data object to determine differences between the stored prior state and the current state of the data object other than the effect of the undesired editing operation; and applying the differences to the stored prior state of the data object to obtain a new state of the data object. Each prior state of the data object corresponds to an effect of one of previously performed editing operations on the data object.