WordPress 6.8 Introduced a Resize Handle That Breaks Metabox Auto-Scroll

Since updating to WordPress 6.8, I noticed a surprising UX change in the post editor:
a new resize handle (<button role="separator">) appears at the bottom of the classic meta boxes area.

The issue

This UI change breaks the expected behavior of plugins that use classic meta boxes — like SEOPress or ACF.
On my site facla.ro, the SEO metabox is no longer fully visible unless I manually drag the resize handle.

Previously, in WordPress 6.7, the editor would auto-expand to show all meta boxes without user intervention.

Tested environment

• WordPress: 6.8 (issue), 6.7 (working fine)

• Theme: Mismo

• Plugins: SEOPress, ACF

• Gutenberg Plugin: Not installed

• Browser: Chrome 123

• OS: Windows 11

Temporary Workaround

As a temporary fix, I used the plugin “WP Downgrade | Specific Core Version” to roll back to version 6.7 and everything works perfectly again.

Open question

Is this behavior intentional or a regression in WordPress core?

Would love to hear if others are experiencing the same issue or found a better workaround.

Let’s connect

If you're facing the same bug or have insights, feel free to drop a comment or connect.
I'm posting here to share findings, help others, and gather feedback.