[App][Review] Regression: Bring back folder hierarchy/tree view in diff file list (review pane)

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

26.224.1209

What subscription do you have?

Pro

What platform is your computer?

Darwin 25.3.0 arm64 arm

What issue are you seeing?

Since updating to 26.224.1209, the folder tree/hierarchy in the Review/Diff pane is gone

In the Review/Diff pane, the previous right-side folder hierarchy (tree view) that listed only the changed paths/files appears to be removed. This makes reviewing changes significantly less usable, especially in projects/monorepos with multiple top-level areas (server/client/ui, etc.).

Previously:

• Right side showed a compact folder tree of ONLY changed folders/files
• Next to it: the diff content
• I could quickly understand where changes happened and navigate file-by-file within the relevant folders

Now:

• The tree/hierarchy is gone
• Review becomes a long scroll through diffs with much less context and navigation

This is a major regression for code review workflows and forces me back into the IDE.

What steps can reproduce the bug?

1. Open Codex macOS app
2. Open a git repo with changes across multiple folders (e.g., server/, client/, ui/)
3. Open the Review/Diff pane
4. Observe: no folder hierarchy/tree, only a flat/scroll-based diff review experience

What is the expected behavior?

Bring back the previous folder hierarchy/tree view (showing only changed folders/files) in the Review/Diff pane.
Ideally as:

• Default behavior (like before), or
• A toggle: Tree view vs Flat list

Why this matters

The tree view provided instant structural context and fast navigation for reviewing changes. Without it, code review is much slower and less reliable.

Additional information

• Codex App version: 26.224.1209