# Is there any way to know if annotation is manipulated using undo redo

**URL:** <https://pdfjs.community/t/is-there-any-way-to-know-if-annotation-is-manipulated-using-undo-redo/256>\
**Category:** Technical Support\
**Created:** [September 14, 2020, 10:39am UTC](https://pdfjs.community/t/is-there-any-way-to-know-if-annotation-is-manipulated-using-undo-redo/256 "2020-09-14T10:39:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![vivek.sonawane](https://avatars.discourse-cdn.com/v4/letter/v/e95f7d/32.png) [@vivek.sonawane](https://pdfjs.community/u/vivek.sonawane)\
**Post date:** [September 14, 2020, 10:39am UTC](https://pdfjs.community/t/is-there-any-way-to-know-if-annotation-is-manipulated-using-undo-redo/256/1 "2020-09-14T10:39:55Z")

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Hi ,  
We are trying to get to know whether annotations in viewer are added/modified/deleted by using AnnotationHistoryManager undo redo methods. Is it possible to know these type of events? if yes then how can we achieve this?

Thank you,  
Vivek Sonawane

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<div class="post-metadata">

**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\
**Post date:** [September 15, 2020, 2:31pm UTC](https://pdfjs.community/t/is-there-any-way-to-know-if-annotation-is-manipulated-using-undo-redo/256/2 "2020-09-15T14:31:13Z")

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Hi,

The [annotationChanged](https://pdfjs.express/api/CoreControls.AnnotationManager.html#event:annotationChanged__anchor) event has a third parameter which is an object containing `isUndoRedo`

Thanks,  
Logan