[BUG] Claude Desktop crashes on Japanist (Oyayubi-Shift / 親指シフト) IME input after Electron 44 (Chromium 152) update

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?

Summary

Since updating Claude Desktop to a build that bundles Electron 44 (Chromium 152)
(changelog: v1.49585.0, 2026-09-08), the app crashes when receiving input from
Japanist 10 in Oyayubi-Shift (親指シフト / thumb-shift) mode.

This looks like the same underlying Chromium/Windows IME-composition regression
that hit Google Chrome and Microsoft Edge after they moved to Chromium 151/152
with Japanist — see community reports below. Since Claude Desktop's embedded
Chromium jumped to the same version line in v1.49585.0, it appears to have
inherited the same bug.

What Should Happen?

The composed text should be confirmed normally and appear in the chat input box, the same way it does with Microsoft IME or other IMEs. Claude Desktop should not crash when confirming a conversion typed with Japanist (Oyayubi-Shift).
変換したテキストが正常に確定され、他のIME（Microsoft IME等）を使ったときと同様に、
チャットの入力欄にそのまま表示されるべきです。Japanist（親指シフト）で変換を確定した際に
Claude Desktopがクラッシュしないことを期待しています

Error Messages/Logs

Steps to Reproduce

Steps to reproduce

1. Set Japanist 10 as the active IME, in Oyayubi-Shift mode.
2. Open Claude Desktop and focus the chat input box.
3. Type Japanese text using thumb-shift key combinations.
4. Press Enter to confirm the kana-to-kanji conversion.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.52386.6

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_