undo can't take effect

[William-egg]

normally,ctrl+z is undo shortcut key in windows, but the app can't use it to undo the latest ooperation

[GitHubRulesOK]

it is never possible to really undo Adobe Annotation without an editor, thogh is it has not been saved you can add the deleted copy too. It is a quirk of Adobe Design for appending comments where even a deleted comment cannot be unsaid. The editor needs a complex rebuild of the file to redact dead entries. This is a duplicate of some earlier question so may close if I can find that.