Built-in diff viewer does not keep horizontal scrollbar visible when vertical scrolling is needed

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

26.313.41514

What subscription do you have?

Pro

What platform is your computer?

Microsoft Windows NT 10.0.22631.0 x64

What issue are you seeing?

The built-in viewer has a usability bug with wide content.

If a file/diff needs both vertical and horizontal scrolling, the horizontal scrollbar is only reachable at the bottom of the entire content area. That means I cannot horizontally inspect long lines while I am in the middle of the document; I first have to scroll all the way down to access the horizontal scrollbar.

Expected: the horizontal scrollbar should stay visible/pinned to the bottom of the viewport, or there should be another always-available horizontal scrolling mechanism.

Actual: horizontal scrollbar is only visible at the bottom of the full content.

This is particularly painful in diffs and code review.

What steps can reproduce the bug?

Steps to reproduce

1. Open a file or diff in the built-in viewer.
2. Make sure the content is:

• wide enough to require a horizontal scrollbar, and
• tall enough to require a vertical scrollbar.

1. Try to scroll horizontally while viewing content somewhere in the middle or upper portion of the document.

Expected behavior

The horizontal scrollbar should remain accessible while the content area is vertically scrollable.

Examples of acceptable behavior:

• keep the horizontal scrollbar pinned/sticky at the bottom of the viewport, or
• provide another always-accessible way to horizontally pan wide content.

Actual behavior

The horizontal scrollbar only appears at the bottom of the full scrollable content area, so I have to scroll vertically all the way down before I can access it.

Why this is a problem

This is especially annoying in diffs/code review, where a long line near the top or middle of the file needs horizontal inspection, but the scrollbar is not available unless I first scroll to the bottom.

Environment

• App: OpenAI Codex Windows app
• OS: Windows
• Viewer: built-in diff/file viewer

Notes

I attached screenshots showing:

• wide diff content that clearly needs horizontal scrolling
• the horizontal scrollbar only being available at the very bottom

What is the expected behavior?

The horizontal scrollbar should remain accessible while the content area is vertically scrollable.

Additional information

_No response_