⚠️ 提醒：Chromium 149+ IME 回归导致中文输入异常（非本库问题）

[ale-160]

⚠️ Heads Up: Chromium 149+ IME Regression Causing Chinese Input Issues (Not a Library Bug)

English | 中文

PS: English Version completed with the assistance of translation tools

A Note Before You Read

This is not a request for you to fix code — we want you to be aware and help communicate this to the community.

Our team's technical capabilities are limited — much of the verification process was assisted by AI tools. This English Issue was drafted with the help of translation tools; the Chinese version is the reviewed and authoritative one.

We kindly request the @uiw/react-codemirror team to help verify this issue. In parallel, we have also submitted an Issue to the CodeMirror official team requesting their help in verifying and escalating this to the Chromium team. If this issue is confirmed, you may want to post an announcement or pin this Issue for your users. Our verification process also documents alternative solutions, such as using browsers prior to certain Chromium versions.

Detailed technical analysis report (completed with the assistance of translation tools)

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Issue Description

A Chromium engine regression (149.0.7827.103+) on Windows desktop causes the first IME composition input to be silently lost in all CodeMirror 6 editors. This also affects @uiw/react-codemirror users.

We have confirmed this is not a @uiw/react-codemirror issue — the bug persists even when:

• Completely bypassing @uiw/react-codemirror and using CodeMirror 6's native EditorView API
• Removing all controlled value prop synchronization
• Disabling the internal typingLatch mechanism

Environment

Package	Version
@uiw/react-codemirror	4.25.10
@codemirror/view	6.43.0
@codemirror/state	6.6.0
React	19.2.4
Next.js	16.2.4
Browser (affected)	Chrome 149.0.7827.102, Edge 149.0.4022.62 (Chromium 149.0.7827.103)
Browser (unaffected)	Microsoft Edge 149.0.4022.52 (Chromium 149.0.7827.54), Quark Browser (Chromium 144.0.7559.86), Firefox 150/151, Electron built-in browser (Chromium 142.0.7444.235)
OS	Windows 11
IME	Microsoft Pinyin, QQ Pinyin

Symptoms

• Microsoft Pinyin: Chinese punctuation (。，：) requires two presses per character. First press → nothing. Second press → character appears.
• QQ Pinyin: All IME input (characters + punctuation) requires two attempts. First composition always lost, second succeeds. Some symbols also move the input cursor, e.g. 【 】 ' '.
• Root cause: Chromium 149.0.7827.103+ suppresses the first IME composition events entirely — no compositionstart, beforeinput, or compositionend events are dispatched.

Browser Comparison

Browser	Affected?
Chrome 149.0.7827.102	YES
Edge 149.0.4022.62	YES
Edge 149.0.4022.52 (Chromium 149.0.7827.54)	No
Firefox 150/151	No
Quark Browser	No
Electron built-in browser	No

Why This Matters to @uiw/react-codemirror

This is most likely a Chromium bug rather than a library issue, but users encountering the bug will likely:

1. Suspect the React wrapper or the editor configuration is at fault
2. Search @uiw/react-codemirror Issues for similar reports
3. Potentially file Issues here thinking it's a library problem

Suggested Action

1. Pin this issue as a known upstream bug, so users who encounter it can immediately find the explanation
2. Add documentation (or a warning banner in the README) about the Chromium 149+ IME regression
3. Monitor the Chromium tracker for the fix so you can update your documentation when it's resolved

Alternative Solutions (from our verification)

If you want to recommend temporary workarounds to your users:

• Use browsers with Chromium versions prior to 149.0.7827.54, or switch to Firefox or Quark Browser
• For Chrome or Edge users, avoid upgrading the browser version (disable auto-update, do not check version — checking version may trigger auto-update)

Reproduction

Then open our online demo https://web-text.ale160.com/ or CodeMirror official try page https://codemirror.net/try/ on Windows with Chrome 149+, switch to Microsoft Pinyin, and try typing Chinese punctuation.