After updating to WordPress 6.8, I observed an unexpected UI change in the post editor. A new resize handle has appeared at the bottom of the meta boxes area, specifically for plugins like SEOPress. This new element causes a regression in the expected behavior, breaking the automatic scrolling of meta boxes.

Issue details:

• Expected behavior: The meta boxes (such as SEOPress) should auto-expand and allow scrolling to view all settings.
• Observed behavior: The meta boxes no longer auto-expand. I now have to manually resize the area to access the hidden content, such as SEO settings.
• Affected version: This issue was introduced in WordPress 6.8 and was not present in 6.7.

I believe this change is related to the new core/editor update in WP 6.8, rather than a conflict with themes or plugins.

HTML Element Inserted:

<button role="separator" aria-valuenow="10" aria-label="Drag to resize" aria-describedby=":r9:"></button>

Steps to reproduce:

• Update to WordPress 6.8.
• Go to the “Add New Post” page.
• Scroll down to the Meta Boxes section (e.g., SEOPress, ACF).
• Notice the appearance of a resize handle () at the bottom of the meta boxes.
• Observe that the auto-scroll functionality is no longer working as expected.
• Attempt to manually drag the separator to reveal hidden meta box content.

Environment info:

• WordPress Version: 6.8 (issue), 6.7 (no issue)
• Theme: Mismo
• Plugins: SEOPress
• Browser: Chrome 123, Firefox
• OS: Windows 11, Desktop
• Site for Testing: https://facla.ro/
• Gutenberg Plugin: Not installed

Additional Information:

• I have tested with all plugins deactivated except SEOPress and have confirmed that the issue persists.
• The theme used for testing is Mismo, and the issue was not present in WP 6.7.

Checklist:

• I have searched existing issues in the repository.
• I have tested with all plugins deactivated except SEOPress.
• I have confirmed the theme type used: Block / Classic