Codex App thread view cannot scroll to the latest output after goal injection and repeated steers during an active turn

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

26.616.10790.0

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?

During a long active Codex App thread, I injected/updated a goal while the model was still working, then sent two additional steering/follow-up messages. After that, the Codex App thread view no longer allowed me to scroll to the true bottom of the conversation. The model appeared to continue generating, and the local rollout JSONL continued to exist/update, but the newest assistant output was not visible in the app's thread viewport.

This looks like a Codex App thread scrolling / bottom anchoring issue rather than a backend/model generation failure.

What steps can reproduce the bug?

1. Open or create a long Codex App thread where the assistant is actively streaming output or running a long task.
2. While the turn is still active, inject or update a goal.
3. Send two additional steering/follow-up messages during the same active turn.
4. Try to scroll to the bottom of the app thread.
5. Observe that the visible app thread cannot reach the latest generated assistant output, even though the local rollout file indicates the session is still active/has recent content.

What is the expected behavior?

When the user is following the latest output, the Codex App thread should remain bottom-anchored. Adding a goal, steer, or follow-up input during an active turn should not make the newest assistant output unreachable in the app thread view.

Additional information

This may be related to existing Codex App thread scroll issues

I reviewed #28755, #29643, and #28718. They look related to the same broad App scrolling / virtualization / scroll anchoring area, but I do not think this report is an exact duplicate.

The key differences are:

• #28755 is triggered after opening an existing long session and pressing the jump-to-bottom button. It then enters an infinite loop alternating between an earlier section, the latest section, and a blank viewport. My issue is not caused by pressing jump-to-bottom and I am not seeing that continuous blank/old/latest loop.
• #29643 describes the output panel continuously jumping up and down by itself while output is being generated or displayed. My issue is not primarily a continuous up/down jumping problem; the main symptom is that the newest assistant output becomes unreachable in the App thread viewport.
• #28718 describes an idle long project thread on Windows where scrolling to read earlier messages causes the scrollbar thumb and viewport to jump. My issue happens during an active turn after a goal update plus additional steering/follow-up messages, and the failure is that I cannot reach the latest generated output.

So this may share an underlying component with those issues, such as long-thread virtualization or scroll anchoring, but the trigger and user-visible failure mode are different enough that I believe it should remain a separate report unless maintainers already know these are the same root cause.