Description

When a Navigation block is added within a Cover block in the header template part, and then a Cover block (using background image and also contains a Post Title block) in the content body is rendered on mobile, the second Cover block overlaps the mobile menu overlay, as if the z-index is greater than the menu.

Step-by-step reproduction instructions

1. In the site editor, create a header template part that is comprised of a Cover block that contains a Navigation block
2. Also in the site editor, outside the header template part, create another Cover block with a background image and Post Title block
3. Save changes, then preview the site in responsive view, particularly the mobile menu

The structure in the site editor should look like this:

Screenshots, screen recording, code snippet

Screen recording:

Environment info

• WordPress Version 13.2.2
• Gutenberg active
• Tested on Chrome
• Was able to reproduce on multiple themes, including Twenty Twenty-Two and Blockbase

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