Cannot prevent cancel when user presses Escape twice

### MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/HTMLDialogElement/cancel_event

### What specific section or headline is this issue about?

_No response_

### What information was incorrect, unhelpful, or incomplete?

"You can uncomment the line containing event.preventDefault() to cancel the event."

### What did you expect to see?

... except if user presses Escape twice. In that case the second preventDefault() is ignored, and the dialog will close. (At least for Firefox and Chrome on Windows)

### Do you have any supporting links, references, or citations?

_No response_

### Do you have anything more you want to share?

_No response_

### MDN metadata

Page report details

* Folder: `en-us/web/api/htmldialogelement/cancel_event`
* MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/HTMLDialogElement/cancel_event
* GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/htmldialogelement/cancel_event/index.md
* Last commit: https://github.com/mdn/content/commit/661a04e7a61abe3d8c7245f04cdd1d0bc865fe69
* Document last modified: 2026-01-26T06:55:57.000Z