[app] Activity view does not highlight the currently open conversation in the sidebar

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

26.727.51351 (build 6119)

What subscription do you have?

ChatGPT account (exact plan does not appear relevant to this client-side UI issue)

What platform is your computer?

Darwin 25.5.0 arm64 arm
macOS 26.5.2 (Build 25F84)

What issue are you seeing?

When Activity view is enabled in the Codex App sidebar, opening a conversation does not visually highlight that conversation as the currently selected item in the left sidebar.

The conversation content opens normally, but the sidebar provides no selected-state indication for the active conversation. This makes it difficult to tell which Activity item is currently open, especially when several conversations have similar titles.

What steps can reproduce the bug?

1. Open the Codex App.
2. Click the bell icon to enable Activity view.
3. Click any conversation listed in Activity view.
4. Observe that the conversation opens in the main pane.
5. Check the same conversation in the left sidebar.
6. The item is not visually highlighted as selected.

What is the expected behavior?

The currently open conversation should retain a clear selected/highlighted state in Activity view, consistent with normal sidebar navigation, so the active conversation is always identifiable.

Additional information

I searched existing issues before filing. The closest report I found is #36300, which concerns stale ordering in Activity view, not the missing selected state. The sidebar history/visibility issues I found also describe different behavior.