You click into the middle of a sentence, type a character, and the cursor moves to the end. Or the new character appears briefly, then vanishes. Before changing editor settings, check whether your React integration is replacing the document or remounting the editor.

This is a diagnostic sequence, not a claim that every cursor issue comes from React state. A browser, plugin or editor defect can produce similar symptoms. A small reproduction helps separate those causes.

First, establish a small reproduction

Open one short paragraph in the React sample. Temporarily remove autosave, remote refresh, live previews and application-specific HTML transformations from the reproduction. Type in the middle, select a word, apply bold, and undo. If the problem remains, keep that small example for investigation. If it disappears, restore integrations one at a time.

Is the editor being remounted?

A changing key tells React to replace a component. Using the current HTML, a timestamp or a random value as the editor key can turn each edit into a fresh editor. Defining an editor component inside its parent’s render can also create an unstable component identity.

Count initialization and cleanup calls in a development reproduction. A fresh mount on each keystroke is different from Strict Mode’s development setup-and-cleanup check. Keep the same identity while editing a document; reset it deliberately when switching documents.

Is old HTML coming back through controlled state?

Trace the value at four points: the editor change callback, local state, the save request and the save response. If local state waits for a debounced request or an older response is written back into the editor, new typing can be replaced with an earlier revision.

Keep local edits current and debounce persistence separately. Record which revision a request saved. A success response can mark that revision as saved without replacing the current draft. When the server detects a conflict, show a recovery flow rather than silently choosing one person’s content.

Are you rewriting content while the user types?

Replacing the full HTML string is different from editing at the current selection. Reformatting tags, changing whitespace or calling setHTMLCode() after every change may turn a harmless render into a document replacement.

Keep security validation on the server, and separate it from visual formatting during input. If your application needs a normalized preview, render that preview separately. Treat externally supplied document replacements as deliberate actions, not a routine response to every keystroke.

Choose the simplest state model that fits

If other fields depend on the current document, use the controlled component and keep one source of truth. If the editor is mostly a form field, an uncontrolled instance seeded by defaultValue can avoid synchronizing every change through a large parent component. Read the current HTML through the ref when submitting.

The React editor state guide contains both code patterns, readiness checks and a document-switching checklist. It also explains why reading a delayed state value can miss the final edit.

Test beyond one English sentence

Type at the start and middle of formatted text, then undo and redo.
Compose Chinese or Japanese text with an IME and verify it is committed once.
Use a phone keyboard, move the caret and paste a short paragraph.
Switch documents while a previous load or save is pending.
Open and close a modal editor, and navigate away and back.
Repeat with a realistic long document; profile serialization and preview updates.

When reporting a remaining issue, include the binding and core versions, browser, a minimal document and whether the editor remounts. Share redacted code and reproduction steps rather than customer content.

Why does the cursor jump in a React rich text editor?