Steps to reproduce:

1. Log in to back office.
2. Go to Product catalog / Product types.
3. Start creating a new product type.
4. Fill in 'Identifier' field.
5. Clean up 'identifier' field.
6. Verify web browser console outpup.

Actual result:
See attached screenshot.

JS exception occurred while user clear identifier filed data.

Uncaught TypeError: Cannot read properties of null (reading 'querySelector')
    at ibexa-admin-ui-layout-js.js:61690:53
    at Array.forEach (<anonymous>)
    at MutationObserver.classChangedCallback (ibexa-admin-ui-layout-js.js:61676:20)

Expected result:

No exception occurs.