[Windows][26.818.2441.0] Update drops UI font size 18 to default and app zoom is focus-dependent

What version of the Codex App are you using?

• Codex Desktop MSIX: 26.818.2441.0 x64
• app-server: 0.148.0-alpha.21
• packaged executable file/product version: 151.0.7922.170

What subscription do you have?

ChatGPT subscription. Exact tier omitted because this is a local Desktop settings migration/UI issue.

What platform is your computer?

Windows 10 Pro 22H2, build 19045, x64.

What issue are you seeing?

After updating Codex Desktop, the entire interface became visibly smaller. The previous app-level font/zoom interaction also appeared to stop working.

The cause is reproducible in the persisted settings migration:

• Pre-update configuration backups contain desktop.sansFontSize = 18.
• The current packaged Desktop schema accepts UI font sizes only from 11 through 16, with a default of 14.
• On the first current-build startup, Desktop logged this twice:

[settings-store] Dropping invalid desktop setting key=sansFontSize

• The old value is dropped rather than clamped/migrated. The running renderer can therefore fall back from 18 to the default 14, producing an obvious update-time size regression.
• The current supported Settings UI can write at most 16, so the previous 18-equivalent appearance cannot be restored through the font preference alone.

There is a second discoverability/focus problem with app zoom:

• The main Codex UI uses a persisted CSS scale state (electron:window-zoom) with 0.1 steps and a 0.5–3.0 range.
• The View-menu/keyboard commands include Ctrl+= / Ctrl++, Ctrl+-, and Ctrl+0.
• If an embedded browser pane has focus, those commands are routed to that pane instead of the main Codex UI. The shortcut then appears to do nothing to the app chrome/sidebar/transcript.
• The current package does not expose an app-wide Ctrl+mouse-wheel handler, although that interaction previously worked for this user.
• The main BrowserWindow also resets native Chromium zoom on load, while the app-wide scale is implemented separately through CSS state. This makes the two zoom concepts difficult to understand and diagnose.

The persisted app zoom itself is working in this reproduction: it currently contains 1.1 (110%). The regression is the silent font migration plus focus-dependent zoom routing, not simply a missing state file.

What steps can reproduce the bug?

Font migration

1. Start from a profile created by an earlier Desktop build with desktop.sansFontSize = 18.
2. Update to 26.818.2441.0.
3. Launch Desktop.
4. Observe that the UI is smaller.
5. Inspect the Desktop log and see Dropping invalid desktop setting key=sansFontSize.
6. Open Settings > General > Appearance > UI font size.
7. Observe that the new maximum is 16.

Zoom focus routing

1. Open the main Codex window.
2. Focus the task area/sidebar and use View > Zoom In or Ctrl+=; the app-level CSS scale changes.
3. Focus an embedded browser pane.
4. Use the same command.
5. Observe that only the browser pane zoom changes, while the main Codex interface does not.
6. Try Ctrl+mouse-wheel; no app-wide zoom occurs.

What is the expected behavior?

• Existing font preferences should be migrated without a surprise visual regression.
• If 18 is no longer supported, migration should clamp to 16 (or compute an equivalent app zoom) instead of silently dropping to the default 14.
• Ideally, retain the previous supported maximum or present a one-time migration notice.
• App zoom should have one visible percentage control and clearly distinguish “zoom Codex UI” from “zoom embedded page.”
• The focused embedded browser should not silently hijack the only apparent app-wide zoom shortcut.
• A mouse-wheel zoom gesture should either continue to work or the UI should clearly expose its replacement.
• Font and app zoom settings should remain persistent across restart.

Additional information

Related but not duplicate:

• #23139 requests a native app-level UI scale control.
• #16761 reports controls breaking after zoom.
• #31940 reports detached-window zoom routing.

This report adds a concrete current-build settings-schema migration failure (18 becomes invalid and is dropped) plus the embedded-pane focus-routing behavior.

No usernames, local absolute paths, profile contents, account identifiers, screenshots, conversation data, or raw logs are attached. No application bundle or state file was modified during diagnosis.

Start with the persisted settings migration and validation that logs “Dropping invalid desktop setting key=sansFontSize,” then inspect the View-menu and keyboard zoom command routing when an embedded browser pane has focus. Done means older font settings no longer regress to the default, app zoom remains persistent, and app-level zoom commands are distinguishable from embedded-page zoom.