Codex Desktop Markdown preview treats soft line breaks as hard breaks

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

Version 26.616.41845 • Released Jun 19, 2026

What subscription do you have?

Pro plan

What platform is your computer?

Darwin 24.6.0 arm64 arm

What issue are you seeing?

In the Codex Desktop app, the rendered Markdown preview treats ordinary newlines inside a paragraph as visible hard line breaks.

This is specifically about the app-side Markdown preview for local .md files, not the TUI.

VS Code's Markdown editor and VS Code Markdown Preview both handle the same file as expected: source newlines used for authoring/wrapping do not become hard visual breaks in the rendered paragraph. Codex Desktop preserves those source newlines visually, so wrapped Markdown source becomes ragged rendered prose.

What steps can reproduce the bug?

1. Create a local Markdown file with a paragraph that is manually wrapped across source lines:

# Selected-Change Diff

## Why

After the log refresh loop, the next useful product slice is diff inspection for the selected
change. It should reuse the same mental model: open the current target, refresh manually, preserve
context, and return to the log.

1. Open the file in Codex Desktop's rendered Markdown preview.
2. Compare with VS Code Markdown Preview for the same file.

Codex Desktop renders the newline after selected and other source-wrapped newlines as visible line breaks. VS Code Markdown Preview renders the text as normal flowing paragraph text.

What is the expected behavior?

A single newline inside a paragraph should be treated as a Markdown soft break, matching normal Markdown preview behavior in tools like VS Code/GitHub.

It should not force a visible line break unless the Markdown uses an explicit hard break, such as two trailing spaces or <br>.

Additional information

Screenshots compare:

1. VS Code Markdown source
2. VS Code Markdown Preview
3. Codex Desktop Markdown preview

The Codex preview appears to preserve paragraph source newlines visually, likely equivalent to applying whitespace-preserving rendering to paragraph content.