claude-code - 💡(How to fix) Fix [BUG] Scrollback duplication on terminal resize persists in 2.1.116 (VS Code integrated terminal, macOS) [5 comments, 4 participants]

Preflight Checklist

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

What's Wrong?

Summary

The scrollback duplication on resize bug noted as fixed in v2.1.116 still reproduces in my environment. Each terminal resize during a Claude Code session pushes a full snapshot of the current TUI into terminal scrollback. Multiple resizes produce stacked duplicates of the splash screen / current view.

The fix from v2.1.116 ("Fixed scrollback duplication in inline mode where resizing the terminal or large output bursts would repeat earlier conversation history") appears to be incomplete for this environment combination.

Likely related to / possible duplicate of #18493.

Environment

• Claude Code: 2.1.116
• VS Code: 1.116.0 (integrated terminal, panel location)
• OS: macOS 26 (Darwin 25.4.0)
• Hardware: Apple Silicon
• Shell: zsh (default macOS, minimal .zshrc — PATH exports only, no custom prompt)
• Terminal font: JetBrainsMono Nerd Font Mono
• TUI mode: default (the bug does not occur with tui: "fullscreen")

What Should Happen?

Expected: Scrollback shows whatever was in the shell before claude was launched.

Error Messages/Logs

**Actual:** Scrollback contains multiple stacked duplicates of the Claude splash screen, separated by stray characters (e.g. `)`).

The bug appears on the splash screen with zero user input, ruling out hooks, statusline, or any per-turn behavior.

Steps to Reproduce

Reproduction

1. Open VS Code integrated terminal
2. Run claude to start a fresh session
3. Before sending any prompt, resize the terminal panel several times (drag the panel border, or toggle panel maximize)
4. Scroll up in the terminal

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

2.1.116

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

Workaround

Setting "tui": "fullscreen" in ~/.claude/settings.json eliminates the glitch (alt-screen renderer doesn't touch scrollback). However, scrolling inside fullscreen mode is line-by-line and feels noticeably laggier than native xterm.js scrolling, so it isn't a comfortable permanent solution for heavy terminal users.

Ruled out (not the cause)

Exhaustively eliminated as causes:

• VS Code terminal.integrated.gpuAcceleration (on, off, auto — same)
• VS Code terminal.integrated.shellIntegration (disabled — same)
• VS Code terminal.integrated.suggest.enabled (disabled — same)
• VS Code terminal.integrated.stickyScroll.enabled (disabled — same)
• VS Code terminal.integrated.smoothScrolling (disabled — same)
• VS Code terminal.integrated.minimumContrastRatio (removed — same)
• VS Code terminal.integrated.scrollback (varied 1000–20000 — only changes how long duplicates persist before aging out)
• VS Code editor.accessibilitySupport: "on" (set to off — same)
• Terminal font (swapped to Menlo — same)
• Custom statusline (removed — same)
• Custom hooks (logically excluded — they fire on Stop/Notification, but the bug appears pre-turn)
• Plain zsh (no Claude) — resize + scroll works perfectly with all the above settings unchanged

Notes for triage

The bug only manifests when Claude Code is the running process. Same VS Code config + same shell with anything else (vim, less, plain zsh) behaves correctly. So the leak is in Claude Code's main-screen renderer's response to SIGWINCH, not in xterm.js or the shell.