Delete at the beginning of newly created quote deletes the quote, not the first charater.

[tomalec]

Description

I convert a paragraph of text (pasted markdown, or just any text) to a quote block, by adding > at the beginning. Then once the block is converted, I continue expecting the block would behave as if it has been before, and I placed the caret at the beginning. So I press del I'd expect the first character after the caret to be removed.

Then unexpectedly the quote block is converted back to a paragraph. This is the action I'd expect on undo or backspace. del deletes what's after not before the caret.

In Notion and other rich text editors, it behaves as I'd expect.

Step-by-step reproduction instructions

1. Open the editor, like https://wordpress.org/gutenberg/
2. Move caret to the beginning of a paragraph.
3. Type > .
4. Once the block is converted press press del.
5. Continue typing.the

Screenshots, screen recording, code snippet

Environment info

• WordPress 5.9
• Chrome, Firefox
• Ubuntu 20.04

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[ellatrix]

You're right, Delete shouldn't undo it.

[mhkuu]

I found that this is a more generic issue with transforms through prefixes, as I can also reproduce it with creating a list block by prepending * or - . I tracked it down to packages/block-editor/src/components/rich-text/use-undo-automatic-change.js where we allow the automatic change to be undone on pressing the delete, backspace, and escape button. I'll create a PR to remove the DELETE key from the guard so that only backspace and escape triggers the undo 👍