[examples/hovering-toolbar] Typing English text over selected formatted text crashes locally

[wudidewo12]

Description

In the Hovering Toolbar example, typing English replacement text over a selected formatted word crashes the local page. The live reference handles the same action normally.

The tester also observed that Chinese input does not trigger this crash in the same workflow, while English input reliably does.

Recording

Screenshots attached below:

Local actual behavior:

Live reference expected behavior:

Video attached below:

CleanShot.2026-05-08.at.15.37.39.mp4

Sandbox

No standalone sandbox. Reproduced in the Slate examples site.

Local reproduction URL:

http://localhost:3100/examples/hovering-toolbar

Reference URL:

https://www.slatejs.org/examples/hovering-toolbar

Steps

To reproduce the behavior:

1. Go to http://localhost:3100/examples/hovering-toolbar.
2. Double-click the bold word bold in the first paragraph so it is selected.
3. Type English replacement text, such as plain.
4. Repeat the same steps on https://www.slatejs.org/examples/hovering-toolbar.

Expectation

The selected formatted word should be replaced by the typed English text, matching the live reference. The page should not crash.

Actual behavior

On localhost, typing English text over the selected formatted word crashes the page.

Chinese input does not appear to trigger this crash in the same workflow, while English input reliably does.

Environment

• Local URL: http://localhost:3100/examples/hovering-toolbar
• Reference URL: https://www.slatejs.org/examples/hovering-toolbar
• Local branch/commit: v2, ce2bd6c6
• Browser: Chrome
• OS: macOS
• Local app setup: Slate examples site served locally with bun serve

Impact

This breaks a basic rich-text editing workflow in the Hovering Toolbar example. Selecting formatted text and typing normal English replacement text can crash the local page instead of replacing the selected content.

[zbeyens]

🟢 95-100% confidence

Phase	🧪 Tests	🌐 Browser
Reproduced	🔴 Hovering-toolbar replacement row failed in the issue plan	✅ Video showed the local crash
Verified	🟢 Focused hovering-toolbar row passed	✅ English replacement no longer crashes

🌐 Browser Check

• Open http://localhost:3100/examples/hovering-toolbar.
• Double-click the formatted word bold in the first paragraph.
• Type English replacement text, for example plain.
• Confirm the selected word is replaced and the page does not crash.

✅ Outcome

• English text replacement over selected formatted text is stable.
• The page no longer crashes with Cannot destructure property 'path' of 'at' as it is null.

⚠️ Caveat

• Report baseline was ce2bd6c6; current v2 HEAD 07d79634 contains the verified behavior.

🏗️ Design

• Chosen owner: expanded-selection replacement insert target.
• Why not quick patch: catching the crash in the example would leave null-target replacement broken.
• Why not broader change: no IME-specific redesign was needed for the English replacement crash.

🧪 Verified

• PLAYWRIGHT_RETRIES=0 PLAYWRIGHT_BASE_URL=http://localhost:3100 bun playwright playwright/integration/examples/hovering-toolbar.test.ts --project=chromium --grep "typing English over selected formatted text does not crash"
• bun check

[zbeyens]

Closing: current v2 HEAD is verified with 95%+ confidence.