[Bug]: Weird red boxes around certain letters in RTL language #4951

Is there an existing issue for this?

• I have searched the existing issues

OS/Web Information

• Web Browser:
• Local OS:
• Remote OS:
• Remote Architecture:
• code-server --version:

Steps to Reproduce

When writing code/strings in Persian (an RTL language using Perso-arabic alphabet), I see red boxes around certain letters. These boxes appear for both light and dark themes, and various fonts that I checked. See the image below for an example.

Any idea where this comes from?

Expected

Persian text rendered the same way as English text.

Actual

There are red boxes around certain letters in text. You can try this text in the editor (e.g. Python).

'کلمه‌های خط‌ خورده در مصرع نیستند. کلمه‌های زرد رنگ در مصرع به کار رفته‌اند اما در مکان دیگری، و کلمه‌های پررنگ سبز در مصرع و در جای درست حضور دارند.'

Logs

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Screenshot/Video

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Does this issue happen in VS Code?

• I cannot reproduce this in VS Code.

Are you accessing code-server over HTTPS?

• I am using HTTPS.

Notes

No response