Codex Desktop: support a tiled multi-pane workspace for chat, UI preview, source, and tasks

What variant of Codex are you using?

Codex Desktop App for Windows

What feature would you like to see?

Please add a tiled, resizable multi-pane workspace to the Codex Desktop App so users can keep several different work surfaces visible at the same time within one app window.

This is different from opening several independent Codex windows or adding browser-style session tabs. The requested experience is closer to an IDE/workbench layout where mixed panel types can be arranged side by side.

Current pain

During frontend and UI development, I frequently need to see all of the following at the same time:

• the Codex conversation and composer
• a live UI preview in the in-app browser
• the relevant source file or generated file
• a diff/review panel
• background task, subagent, or terminal status

Today, the main conversation can remain visible, but the right-side content generally has to be switched between tabs or surfaces. This forces repeated navigation and makes it difficult to compare the rendered UI with its source code while discussing changes with Codex.

A concrete example is refining an H5 or mini-app interface: I need to inspect the live page and the corresponding source code simultaneously, while keeping the Codex conversation available for instructions and feedback.

Proposed UX

Support dockable/resizable pane groups inside one Codex window:

• split a pane vertically or horizontally
• show two or more panels side by side
• drag a tab into another pane group
• allow mixed panel types, including:
• Codex thread/chat
• in-app browser or live preview
• source/file preview
• diff/review
• terminal
• background tasks/subagents
• resize, collapse, maximize, and close individual panes
• remember the layout per project or workspace
• provide a simple reset-to-default-layout action

Example layout:

┌──────────── Codex conversation ────────────┬──── Live UI preview ────┬── Background tasks ──┐
│                                            │                         ├──────────────────────┤
│                                            │                         │ Source file / diff   │
└────────────────────────────────────────────┴─────────────────────────┴──────────────────────┘

Why this matters

Multiple windows help when work should be separated, but a tiled single-window layout is more useful when several views belong to the same task and must be compared continuously. It also works better on one large monitor because related context stays in a single application frame.

Relationship to existing requests

• #12773 requests multi-window support.
• #18778 requests visible tabs for active sessions.
• #23314 requests multiple tabs within the in-app browser.

This request is specifically for multiple simultaneously visible, mixed-content panes within one Codex Desktop window, such as chat + browser preview + source/diff + background tasks.