[Windows Desktop 26.707.12708.0] Severe lag while typing and switching tasks; repeated 0xc06d007f crashes

What version of the Codex App are you using?

Microsoft Store package: OpenAI.Codex_26.707.12708.0_x64__2p2nqsd0c76g0

What platform is your computer?

Windows 11 Pro, build 26200, x64, 16 GB RAM.

What issue are you seeing?

I am seeing severe, persistent UI lag in the Windows desktop app during normal use.

The most noticeable symptoms are:

• typing into the composer has a visible delay;
• switching between tasks/conversations can freeze the window for several seconds;
• sending a message can feel delayed before the UI accepts it;
• the whole desktop sometimes feels briefly stuck while the app remains open.

This is not just a slow network connection. CPU, disk queue, and available memory were normal while the problem was happening. Windows Event Viewer repeatedly records new Application Error events for ChatGPT.exe:

• Event ID: 1000
• package: OpenAI.Codex_26.707.12708.0_x64__2p2nqsd0c76g0
• exception code: 0xc06d007f
• faulting module: unknown

I also see repeated renderer-side ResizeObserver loop completed with undelivered notifications errors in the desktop logs.

I tried the Windows Repair action and then Reset for the Codex app. The reset started a fresh app process, but the same 0xc06d007f events and severe lag returned within minutes.

What steps can reproduce the bug?

1. Launch Codex Desktop on Windows.
2. Open an existing task, then switch between tasks/conversations.
3. Type or submit messages normally.
4. Observe delayed input and intermittent UI freezes.
5. Check Windows Event Viewer > Windows Logs > Application and observe repeated ChatGPT.exe Event ID 1000 entries with 0xc06d007f.

The problem occurs during ordinary text-based work; no in-app browser or external device is required.

What is the expected behavior?

Typing, switching tasks, and submitting messages should stay responsive. A normal task should not generate repeated background crashes or make the rest of the desktop stutter.

Additional information

I found related reports such as #33518, #33494, and #33524 after collecting the local evidence. I am filing this separately because the same failure is still present on the newer Microsoft Store build 26.707.12708.0, even after both Repair and Reset. I have not attached raw logs because they may include private task content, but I can provide redacted event details if useful.