Input box UI only displays first several lines after pasting long prompt in editor

Description

When using Ctrl+G to open the input box in an external editor, pasting a very long prompt (5000+ lines), then saving and closing the file, only the first several lines appear in the input box UI. The content is there but not displayed.

Steps to Reproduce

1. Press Ctrl+G to open the input box in VS Code
2. Paste a very long prompt (5000+ lines)
3. Save and close the file
4. Observe the input box - only the first several lines are visible

Expected Behavior

The full pasted content should be visible or scrollable in the input box UI.

Actual Behavior

Only the first several lines are shown and not scrollable, though the content is present.

Environment

• Claude Code 2.0.67
• macOS 15.6.1
• VS Code 1.107.0 (arm64)