Undo manager built on step inversion. Groups adjacent-in-time transactions and restores the selection from before each group.
Redo groups; the last entry is what redo reapplies next.
Undo groups, oldest first: the last entry is what undo reverts next.
Record a dispatched document-changing transaction.
Undo manager built on step inversion. Groups adjacent-in-time transactions and restores the selection from before each group.