[BUG] Plan mode: cannot scroll to reach Claude's answers rendered above the plan box

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When Claude presents a plan, it renders inside a bordered box that has its own internal scroll. That box captures scrolling, I can scroll within the plan, but the terminal region above the box is frozen. I can't scroll up to reach anything that was printed before the plan.

This breaks a common plan-mode workflow:

1. Claude shows a plan.
2. I push back or ask a question.
3. Claude replies with answers/explanations, then re-renders the updated plan.
4. Those pre-plan answers appear above the plan box, and are now unreachable, because scrolling only moves content inside the box.
5. The only way to read them is to press Escape and exit plan mode.

The pre-plan answers are usually more useful to me than the plan itself (they explain what changed and why), so having them trapped above an unscrollable box is a real workflow blocker.

Screenshots

1. In plan mode, the answers are above the plan box and I can't scroll to them:

<img width="2560" height="577" alt="Image" src="https://github.com/user-attachments/assets/41dbfad1-e4d1-4233-b3fb-082ef272d389" />

1. Scrolling only moves content inside the plan box; the line above it stays fixed:

<img width="2560" height="445" alt="Image" src="https://github.com/user-attachments/assets/2cdc8678-0922-4b6d-a205-b64dd59ec757" />

1. Only after pressing Escape ("User rejected Claude's plan") do the answers become visible:

<img width="2333" height="316" alt="Image" src="https://github.com/user-attachments/assets/6c528961-3a00-49e8-8ac3-75d791b0ff2f" />

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Kind of related to #9001 and #65833

What Should Happen?

While a plan is displayed, I should be able to scroll the full terminal / conversation history, not just the content inside the plan box, so that explanations Claude gives before the plan remain reachable.

Steps to Reproduce

1. Start Claude Code and enter plan mode (claude, then Shift+Tab to plan mode, or ask for a plan).
2. Ask Claude to plan a task large enough that its output spans more than one screen height.
3. When the plan appears, push back or ask a follow-up question (e.g. "before you code, explain X" or "I'm not happy with Y, why did you choose it?").
4. Claude thinks, prints answers/explanations to your question, then re-renders the updated plan in the plan box.
5. Try to scroll up (mouse wheel / trackpad / PgUp) to read the answers that appeared above the plan box.

Result: Scrolling only moves content inside the plan box. The region above the box — where the answers are , is frozen and unreachable. The answers become visible only after pressing Escape to exit plan mode.

Claude Model

Opus

Is this a regression?

Not a regression, I never had this exact (fixed) problem before, so it's a new feature that is gone wrong.

Last Working Version

2.0.xx

Claude Code Version

2.1.202

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2