[examples] Cmd+Z after text input moves the caret to the beginning of the current line

[wudidewo12]

Description

After typing normal text in the middle of an existing line and pressing Cmd+Z, the caret can jump to the beginning of the current visual line.

This is not specific to examples/editable-voids. The tester observed the same caret restoration problem across multiple Slate examples.

This is separate from the Chinese IME composition issue. This issue uses normal text input followed by Cmd+Z.

Recording

Screenshots attached below:

Local actual behavior:

Live reference expected behavior:

Video attached below:

CleanShot.2026-05-07.at.15.08.39.mp4

Sandbox

No standalone sandbox. Reproduced in the Slate examples site.

Local reproduction URL examples:

http://localhost:3100/examples/plain-text

http://localhost:3100/examples/richtext

http://localhost:3100/examples/images

http://localhost:3100/examples/editable-voids

Live reference URL examples:

https://www.slatejs.org/examples/plain-text

https://www.slatejs.org/examples/richtext

https://www.slatejs.org/examples/images

https://www.slatejs.org/examples/editable-voids

Steps

To reproduce the behavior:

1. Open any Slate example with editable text, such as examples/plain-text, examples/richtext, examples/images, or examples/editable-voids.
2. Click in the middle of an existing visual line of text.
3. Type a short marker string, such as abc.
4. Press Cmd+Z.
5. Observe where the caret is restored after the typed text is undone.

Expectation

After undoing the typed text, the caret should remain near the original edit position.

Live reference expected behavior:

• The typed text is undone.
• The caret does not jump to the beginning of the current visual line.

Actual behavior

Local actual behavior:

• The typed text is undone.
• The caret jumps to the beginning of the current visual line.

Environment

• Slate Version: v2 branch, commit ce2bd6c6
• Operating System: macOS
• Browser: Chrome
• Local examples site: http://localhost:3100
• Live reference site: https://www.slatejs.org
• TypeScript Version: No response

Context

This is a cross-example caret/selection restoration issue after normal typing and undo. It should be tracked separately from:

• Chinese IME composition caret offset issues.
• Editable Voids runtime crashes during focus/undo interactions.

[wudidewo12]

Additional Mentions evidence:

The same Cmd+Z caret restoration issue also appears in examples/mentions, but the final caret position is different from the plain-text cases.

What the attached video shows:

1. The caret starts near the existing mention inline nodes in the Mentions example.
2. Normal committed text is typed.
3. Cmd+Z is pressed.
4. The typed text is undone, so the document content itself is restored.
5. However, the caret is not restored to the original edit point. Instead, it moves to the wrong position near the mention / inline-node boundary.

This looks like the same caret restoration issue as the other examples. The visible final position is different because the Mentions document contains inline mention nodes, so the incorrect restoration point appears near an inline-node boundary rather than simply at the beginning of a plain visual line.

Video attached below:

CleanShot.2026-05-07.at.18.30.34.mp4

[zbeyens]

🟡 80-94% confidence

Phase	🧪 Tests	🌐 Browser
Reproduced	✅ Issue video shows undo restoring text while the caret jumps to line start	✅ Reported on local examples
Verified	🟢 Plain Text undo/caret proof is green on current v2 07d79634	⚠️ Broader cross-example scope still needs repro

🌐 Browser Check

• Open http://localhost:3100/examples/plaintext.
• Click in the middle of editable text.
• Type a short marker string.
• Press Cmd+Z.
• Confirm the typed text is undone and the caret stays at the edit point.

✅ Outcome

• Current v2 passes the Plain Text undo/caret row for this bug class.
• The verified row restores the caret near the original edit position after undo.

⚠️ Caveat

• The issue also names richtext, images, and editable-voids. This pass did not manually verify every listed example, so I am leaving this open until those routes are either reproduced or confirmed green.

🏗️ Design

• Chosen owner: history selection restore and DOM caret placement.
• Why not quick patch: the current focused proof is already green for the Plain Text route.
• Why not broader change: broader cross-example closure needs exact route proof, not a generic assumption.

🧪 Verified

• cd /Users/zbeyens/git/slate-v2 && PLAYWRIGHT_RETRIES=0 PLAYWRIGHT_BASE_URL=http://localhost:3100 bun playwright playwright/integration/examples/plaintext.test.ts playwright/integration/examples/mentions.test.ts playwright/integration/examples/paste-html.test.ts playwright/integration/examples/iframe.test.ts --project=chromium --grep "keyboard undo restores caret after middle-line typing|keyboard undo restores partial selected text replacement|keyboard undo restores select-all replacement content|copies and pastes a selected mention without crashing|cuts a selected mention without crashing|pastes copied rendered Slate content as an internal fragment before HTML import|applies parent toolbar formatting to selected iframe text"
• cd /Users/zbeyens/git/slate-v2 && bun check