›_ Codex Issues
Codex Issues / #29759

Windows: Japanese text rendering is noticeably worse than ChatGPT Desktop

Open 💬 0 comments Opened Jun 24, 2026 by chitoku

What version of the Codex App are you using (From “About Codex” dialog)?

Version 26.616.51431 • Released Jun 20, 2026

What subscription do you have?

Corporate/Enterprise

What platform is your computer?

Windows 11 25H2 (26200.8655)

What issue are you seeing?

What issue are you seeing?

Japanese text rendering quality in Codex Desktop is noticeably worse than in ChatGPT Desktop on the same Windows 11 machine.

The text appears to use a different CJK fallback font, resulting in:

  • Japanese text looking smaller than expected
  • Reduced readability
  • Jagged appearance at normal UI scale
  • Glyph shapes that resemble Chinese font fallbacks rather than typical Japanese UI fonts

This issue is visible in regular chat content and markdown text.

ChatGPT Desktop on the same machine renders the exact same Japanese text correctly and is much easier to read.

What steps can reproduce the bug?

  1. Install Codex Desktop on Windows 11.
  2. Use English (United States) as the Windows display language.
  3. Install the Japanese language pack.
  4. Open a conversation containing Japanese text.
  5. Compare the rendering against ChatGPT Desktop on the same machine.

Example text:

東京都写真美術館
葛飾区
令和
日本語の表示品質を確認するためのサンプル文章です。

What is the expected behavior?

Japanese text should render with comparable quality to ChatGPT Desktop.

The application should use an appropriate Japanese font fallback and maintain good readability at normal UI sizes.

Rendering should be consistent across OpenAI desktop applications running on the same system.

Additional information

This does not appear to be a Windows configuration issue because ChatGPT Desktop renders Japanese text correctly on the same machine.

Environment:

  • Windows 11
  • Display language: English (United States)
  • Japanese language pack installed

I suspect the issue may be related to the font stack or CJK font fallback configuration used by Codex Desktop.

I can provide side-by-side screenshots comparing ChatGPT Desktop and Codex Desktop if helpful.

What steps can reproduce the bug?

Type this and send on Codex desktop app.

以下のテキストをそのまま表示（Echo）してください。フォントチェック用です。

東京都写真美術館
葛飾区
令和
日本語の表示品質を確認するためのサンプル文章です。

Here is what you see on Codex desktop app.

<img width="1002" height="430" alt="Image" src="https://github.com/user-attachments/assets/efa60c25-9188-4c67-a066-185fe27051d7" />

What is the expected behavior?

Here is what you see on ChatGPT desktop app. (Much better text rendering quality)

<img width="869" height="465" alt="Image" src="https://github.com/user-attachments/assets/78a92ad3-2197-4fef-9100-0fa4cc01de2d" />

Additional information

_No response_

View original on GitHub ↗