New Category popover Save button submits the whole form instead of the popover form

[slax57]

What you were expecting:
When I add a new Category while editing a Post in the simple demo, the new Category is created and I stay on the Post edition form.

What happened instead:
When I click on the Save button inside the "New category" popover, the whole Post is submitted and I am redirected to the Post List, instead of staying on the Post Edit page.

Steps to reproduce:

1. Go to the simple demo https://codesandbox.io/s/github/marmelab/react-admin/tree/master/examples/simple
2. Edit a Post
3. In the Miscellanous tab, click on Category to edit Categories
4. Click "Create"
5. Fill in a new category name, and click "Save"
6. You are redirected to the List instead of staying on the Edit page

Environment

• React-admin version: 4.0.4
• Last version that did not exhibit the issue (if applicable):
• React version: 18.2.0
• Browser: Chrome
• Stack trace (in case of a JS error):