2 Fullscreen window layout can obscure the text input and working area on Windows

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

Versione 26.825.51511

What subscription do you have?

chatgpt pro

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

When the ChatGPT / Codex desktop app is used in fullscreen mode on Windows, switching between areas or showing the system/navigation bar can obscure part of the working area, including the text input field.
This makes the app difficult to use during active work, because the user has to move between chat, previews, side panels, and input controls while parts of the interface are hidden or covered.

What steps can reproduce the bug?

1. Open the ChatGPT / Codex desktop app on Windows.
2. Put the app in fullscreen mode.
3. Work with chat, previews, or side panels open.
4. Move between areas or trigger the system/navigation bar.
5. Observe that part of the app interface, including the text input area, can be obscured.

What is the expected behavior?

fullscreen mode should preserve a safe visible area for the text input, chat messages, previews, and main controls. If a bar or overlay appears, the layout should adapt so it does not cover essential UI elements.

Additional information

This is a separate issue from the non-draggable voice overlay bug, although both affect the usability of the app during real project work.

No source files or tests are named. Reproduce the issue in the Windows Codex desktop app, then locate the fullscreen and layout handling entry points. Done means the text input, chat, previews, side panels, and main controls remain visible when system or navigation bars appear.