Browser preview expanded panel overlays sidebar hover UI in Codex app

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

26.611.62324

What subscription do you have?

Plus

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

When using the browser preview in the Codex app, the expanded browser panel appears to stay on top of other Codex UI elements. This causes overlay/z-index issues with the sidebar hover state.

For example, when the sidebar is hidden, hovering over the sidebar button shows the sidebar preview/hover panel. But if the browser preview has been opened and expanded, the browser viewport remains layered above the sidebar hover UI. As a result, the sidebar hover panel is partially or fully covered by the browser viewport.

I noticed this started happening after one of the recent updates. It seems like the browser viewport is now always rendered above everything else, even UI elements that should appear on top.

What steps can reproduce the bug?

1. Open the Codex app.
2. Open a browser preview for a local app.
3. Use the “expand panel” option on the browser preview.
4. Hide the sidebar.
5. Hover over the sidebar button to reveal the sidebar hover UI.
6. The browser viewport remains on top of the sidebar hover UI.

What is the expected behavior?

The sidebar hover UI should appear above the browser preview when the user hovers over the sidebar button, even if the browser preview is expanded.

Additional information

Possibly related to issues #25356, #20886, #22363.