Undo reverses the most recent modification, restoring the open document to the state it was in just prior to that modification. This can be repeated to step backward through all changes to the document since it was opened. After undoing an action, you can use [link=redo]Redo[/link] to reapply the change that was undone, as long as another change has not been made since the last undo. You can also revert a document to its last saved state by using the [link=revert]Revert[/link] command.

If undoing an interactive edit operation, you can also use [link=resume_last_operation]Resume Last Operation[/link] to return to the interactive state of that operation with the ability to tweak its parameters. This may be more convenient than undoing and restarting the edit operation from scratch.