macOS: Codex and its update dialog open on built-in display despite external main display

What version of the Codex App are you using?

26.803.41515 (build 6321)

What subscription do you have?

Pro

What platform are you using?

• macOS 26.5.2 (Apple Silicon / arm64)
• Built-in display: 3456 × 2234 Retina
• External main display: DELL U2723QE, 3840 × 2160, UI scaled to 1920 × 1080 at 60 Hz
• Additional external display: LG HDR 4K, 3840 × 2160, UI scaled to 1920 × 1080 at 60 Hz
• Mirroring is off for all displays.

What issue are you seeing?

Codex Desktop always opens its window on the built-in MacBook display, even though the DELL U2723QE is configured as macOS's Main Display.

This is not just an initial-window restoration problem. I have moved and kept the ChatGPT/Codex desktop window on the DELL display, fully quit the app, and reopened it. Codex still appears on the built-in display.

The same placement bug affects the app's Check for Updates dialog: even while the main ChatGPT desktop window is on the DELL display, choosing Check for Updates opens the Software Update dialog on the built-in display.

Steps to reproduce

1. Connect a MacBook's built-in display plus external DELL U2723QE and LG HDR 4K displays, with mirroring disabled.
2. In macOS Display settings, set the DELL U2723QE as Main Display.
3. Move the ChatGPT/Codex desktop window to the DELL display and fully quit the app.
4. Launch Codex Desktop from the DELL display.
5. Observe that the Codex window opens on the built-in display.
6. With the main app window on the DELL display, select Check for Updates.
7. Observe that the Software Update dialog also opens on the built-in display.

Expected behavior

Codex's initial window and its modal update dialog should open on the main display, or at minimum on the display containing the active Codex window. They should not consistently fall back to the built-in display.

Additional information

I also tried resetting the saved ChatGPT main-window frame via defaults delete com.openai.chat "NSWindow Frame ChatGPTMainAppWindow"; it did not change this behavior.

This seems related to the broader macOS external-display coordinate issues in #37270 and #24008, but the reproducible failure here is specifically launch/dialog display selection. I can provide screenshots of the display arrangement and the update dialog if helpful.

Start by reproducing launch and Check for Updates with the DELL display set as macOS's Main Display and the Codex window moved there. Trace the launch window and update-dialog entry points, then verify that both open on the main display or the display containing the active Codex window across the described multi-display setup.