[BUG] Slash-command menu: large blank gap pushes suggestion list off-screen (Windows, v2.1.219)

What's Wrong?

When invoking the slash-command menu (typing / at the prompt), a large blank vertical gap renders between the welcome banner and the command-suggestion list, pushing the list toward the bottom of the terminal. As a result, only the last 1-2 matching commands/skills are visible — the rest of the list is not displayed and does not appear to be reachable by scrolling.

This looks like the same root-cause layout bug reported in #66089 and #66191 (large blank gap between welcome box and prompt box on launch, caused by the v2.1.168 "bottom-anchored input" layout change miscalculating available terminal height on some OS/terminal combinations). Those issues were auto-closed by the stale-bot for inactivity, not because the underlying bug was fixed — and this report shows the same symptom still present at v2.1.219, manifesting in the slash-command completion list rather than at startup.

Environment

• OS: Windows 11 Home, build 10.0.26200
• Claude Code version: 2.1.219
• Node: 24.13.1
• Terminal: Windows Terminal (dedicated "Claude Code" pinned profile/tab)
• Reproduces identically in: that Windows Terminal profile, plain cmd.exe, PowerShell, and Git Bash — both standalone and inside Cursor's integrated terminal

Steps to Reproduce

1. Open a terminal on Windows (reproduces across cmd.exe, PowerShell, Git Bash, Windows Terminal, and Cursor's integrated terminal)
2. cd into a project directory containing custom skills/slash-commands
3. Run claude
4. At the prompt, type /
5. Observe the command-suggestion list

Expected Behavior

The full list of matching slash commands/skills renders directly below the input, scrollable if it exceeds the terminal height.

Actual Behavior

A large empty/blank region renders above the suggestion list, and only the last couple of entries are visible — the rest of the list is effectively hidden, not just scrolled.

Is this a regression?

Yes — matches the layout regression introduced around v2.1.168 described in #66089, still present at v2.1.219.

Related issues

• #66089
• #66191