VS Code: long user prompt cannot be collapsed (expand/collapse toggle unresponsive)

Summary

In the VS Code extension, a long user prompt at the top of the conversation sometimes cannot be collapsed. The expand/collapse toggle (chevron) that normally folds a long user message away does not respond, so the full prompt text stays permanently expanded and occupies a large part of the panel.

This appears related to the existing thinking-block chevron regressions (#61679, #55120, #64803, #64714), but here it affects a user prompt block, not a thinking block. I could not find an existing issue covering the user-prompt case specifically.

Steps to reproduce

1. Open the Claude Code chat panel in VS Code.
2. Submit a long multi-line user prompt (e.g. a big /goal ... block, many lines of text).
3. The prompt renders expanded at the top of the conversation.
4. Try to collapse/fold it.

Expected behavior

The long user prompt shows a working collapse/expand chevron and can be folded away.

Actual behavior

Intermittently, the collapse toggle does not respond (or is not shown), and the long prompt block stays fully expanded with no way to fold it. It does not happen every time.

Environment

• Claude Code: 2.1.197
• VS Code extension: anthropic.claude-code 2.1.197 (darwin-arm64)
• VS Code: 1.126.0
• OS: macOS 26.5.1 (arm64)

Notes

Intermittent — not every long prompt reproduces it. Reloading the VS Code window sometimes restores the toggle. Possibly the same render-state root cause as the thinking-block chevron issues above.