Suggesting mode: after Enter + Backspace inside your own pending insertion, typing over the paragraph is rejected, and on 2.28.0 the editor stops taking input #4119

Versions

• superdoc 2.28.0 / @superdoc/docx-engine 0.27.0: keystrokes rejected, then the render
  worker fails and every later keystroke is dropped.
• superdoc 2.26.0 / @superdoc/docx-engine 0.25.0: the same first keystrokes are rejected,
  but the editor recovers and the rest of the typing lands.
• Measured 2026-10-30 in Bun 1.4.4 under happy-dom, single editor, no collaboration provider
  (the same result inside a y-websocket room). Keys were sent to the editor's own input
  element (textarea[data-v2-ime-host]) as keydown (Enter, Backspace) and as
  beforeinput with inputType: 'insertText', which is how the host receives typing. The
  selection was placed with editor.authoring.setSelectionTarget. This was not run in a real
  browser.

Summary

In Suggesting mode, the user rewrites a paragraph as a suggestion, puts the caret inside their
own inserted text, presses Enter, and then presses Backspace to join the paragraph again. The
paragraph looks unchanged, but the user's insertion is now two tracked changes split at the
join point. When the user then selects the whole paragraph and types over it:

• the first keystrokes come back as edit-rejected ("This edit couldn't be completed. Adjust
  the selection and try again."), and their characters are lost (2.26.0 and 2.28.0);
• on 2.28.0 the next keystroke ends in a render-worker failure: Worker authored annotations have unproved canonical ownership: Authored carrier is absent from its current review group (internalCode: worker-dom.failed, diagnosticCode: RENDER_ERROR). The host removes
  its input textarea, setSelectionTarget returns { ok: false, reason: 'host-not-ready' },
  and every later keystroke is dropped.

Without the Enter + Backspace step, the same type-over works on both versions.

Steps

One .docx with one paragraph: Water the beans at dawn.

import { SuperDoc } from 'superdoc'

const sd = new SuperDoc({
  selector: '#editor',
  document: { type: 'docx', url: './sample.docx' },
  documentMode: 'suggesting',
  user: { name: 'Gardener', email: 'gardener@example.com' },
  onException: (e) => console.log('exception', e.code ?? e.internalCode, e.error?.message ?? e.message),
})
// once ready:
const ed = sd.activeEditor
const blockId = (await ed.doc.blocks.list({ includeText: true })).blocks[0].nodeId
const at = (offset) => ({ kind: 'text', blockId, offset, story: { kind: 'story', storyType: 'body' } })
const select = (a, b) =>
  ed.authoring.setSelectionTarget({ target: { kind: 'selection', start: at(a), end: at(b) }, focus: true })
const ime = () => document.querySelector('textarea[data-v2-ime-host]')
const type = async (s) => {
  for (const ch of s) {
    ime()?.dispatchEvent(new InputEvent('beforeinput', { inputType: 'insertText', data: ch, cancelable: true, bubbles: true }))
    await new Promise((r) => setTimeout(r, 40))
  }
}
const key = (k) => ime().dispatchEvent(new KeyboardEvent('keydown', { key: k, bubbles: true, cancelable: true }))

1. await select(0, 24); await type('Plant peas early and often'). The paragraph reads
   Plant peas early and often as one suggested replacement.
2. await select(15, 15); key('Enter'), wait, then key('Backspace'). The text is the same
   again, but doc.trackChanges.list() now reports two changes:
   replacement "Plant peas earl" and insertion "y and often".
3. await select(0, 26); await type('Sow beans late').
4. await select(len, len); await type(' in rows'), where len is the paragraph's length.

Expected

Step 3 replaces the paragraph with the suggestion Sow beans late, as it does when step 2 is
skipped. Step 4 appends in rows.

Actual

Controls, same build:

• Steps 1, 3 and 4 without step 2: Sow beans late in rows on both versions, no exceptions.
• Enter + Backspace in plain text (no pending insertion), then type-over: correct on both
  versions.
• A second user does step 3 instead of the author: no rejection on either version. Their
  type-over produces two tracked deletions split at the join point (Plant peas earl,
  y and often) and two empty insertions (insertion "").