[BUG] [macOS] Input source (Korean/English) reverts automatically when typing in the chat input field

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet

This looks like a desync between Chromium's cached IME state for the input
field and the actual macOS input source. Related but distinct from existing
CJK IME reports: #21382 (composition failure in Quick Launcher) and #69629
(input field unresponsive) — in this case composition itself works fine;
the problem is that the input source selection silently reverts.

• [x] This is a single bug report
• [x] I am using the latest version of the Claude Desktop app

Environment

• Platform: macOS 26.3.1(25D2128)
• Hardware: MacBook Pro (Apple M4 Pro)
• Claude Desktop version: Claude 1.17377.2 (e0ea9e) 2026-07-01T05:51:58.000Z
• IME: macOS built-in Korean IME (2-Set Korean)
• Input source switch method: Caps Lock (macOS default)

Description

When the chat input field in the Claude Desktop app has focus, switching the
input source between Korean and English does not take effect. The macOS menu
bar indicator correctly updates (한 → A, or A → 한), but as soon as I start
typing in the input field, the input source silently reverts to the previous
language. This happens in both directions (Korean → English and English → Korean).

This only occurs in the Claude Desktop app. The same input source switching
works flawlessly in every other app on the same machine, including browsers
(claude.ai in Chrome/Safari works fine), native macOS apps, and other Electron
apps such as Slack and VS Code.

This looks like a desync between Chromium's cached IME state for the input
field and the actual macOS input source, similar to the known Electron CJK IME
issues (e.g. #21382).

What Should Happen?

Expected Behavior

Typing produces English characters, matching the input source shown in the
menu bar.

Actual Behavior

The input source silently reverts to Korean and typing produces Korean
characters, even though the menu bar briefly showed A. The reverse
(English → Korean) fails the same way.

Workarounds Attempted (none resolved the issue)

• Disabled "Automatically switch to a document's input source" in

System Settings > Keyboard > Input Sources

• Changed the input source switch shortcut from Caps Lock to another key

combination — same behavior with any shortcut

• Quit Logi Options+ entirely to rule out Logitech software interference
• Fully quit (Cmd+Q) and relaunched the app; also reinstalled the app
• Restarted the macOS Korean IME process (killall KIM_Extension)

Partial mitigation: moving focus out of the input field, switching the input
source, then clicking back into the field sometimes avoids the revert. Cmd+R
(reloading the renderer) also temporarily resets the broken state.

Impact

Korean-speaking users cannot reliably mix Korean and English in a single
message, which is a very common pattern (e.g. Korean sentences with English
technical terms). Each language switch requires defocusing the input field or
reloading the app.

Error Messages/Logs

Not specified.

Steps to Reproduce

1. Launch the Claude Desktop app on macOS with both Korean (2-Set) and

English (ABC) input sources enabled.

1. Click the chat input field and type some Korean text.
2. While the input field still has focus, switch the input source to English.

The menu bar indicator changes from 한 to A.

1. Start typing.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

I don't know

Claude Code Version

2.1.177 (Claude Code)

Platform

Other

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_