Add scroll-fix plugin: fixes terminal scroll-to-top regression (all platforms)

[cruzlauroiii]

Summary

Adds a plugin that fixes the terminal scroll-to-top regression affecting all platforms and terminals.

• Automatic fix: Intercepts and clamps cumulative cursor-up within synchronized output blocks to , keeping the cursor within the visible viewport
• Ctrl+6 freeze toggle: Manual output freeze/unfreeze for scrolling through history without viewport being yanked back
• Install script: to patch cli.js directly
• Preload module: for runtime-only fix

Root cause

Ink renderer's emits N cursor-up () sequences where N = previously rendered line count. When N > viewport height, terminals follow the cursor above the visible area, snapping to the top of scrollback. This happens inside synchronized output blocks so even DEC mode 2026 doesn't prevent it — the terminal follows the final cursor position.

Affects all terminals (Windows Terminal, iTerm2, Terminal.app, VS Code, tmux, Kitty, etc.) on all platforms.

Plugin structure

plugins/scroll-fix/
├── .claude-plugin/plugin.json
├── scroll-fix.cjs # Preload module (--require)
├── hooks/hooks.json # SessionStart hook
├── scripts/
│ ├── check-scroll-fix.js # Hook handler
│ └── install.js # CLI patcher (install/uninstall)
└── README.md

Duplicates fixed

• [BUG] Forces scroll to top when outputting code (NOT just when scrolling) #33814 — Forces scroll to top when outputting code
• [BUG] Console scrolling top of history when claude add text to the console #826 — Console scrolling top of history
• [BUG] Terminal scrolls to the top after each response #11801 — Terminal scrolls to the top after each response
• Terminal Scrolling Uncontrollably During Claude Code Interaction #3648 — Terminal scrolling uncontrollably
• [BUG] Terminal scrolls to top during agent execution (Windows Terminal + PowerShell) #34794 — Terminal scrolls to top during agent execution
• [Bug] Scroll position jumps when Claude streams output during upward scrolling #33367 — Scroll position jumps when Claude streams output
• [BUG] CLI crazy scrolling #34242 — CLI crazy scrolling
• [BUG] After the recent updates Claude Code jumps and loses track of scroll position in Terminal window #18299 — Claude Code jumps and loses track of scroll position

Upstream: microsoft/terminal#14774

Test plan

• Verified cursor-up clamping prevents viewport scroll-to-top
• Verified Ctrl+6 freeze/unfreeze works
• Tested on Windows Terminal, VS Code terminal
• Test on macOS (iTerm2, Terminal.app)
• Test on Linux terminals

[cruzlauroiii]

Updated with v2 scroll fix:

• Root cause found: readline/prompt's eraseLines(this.height) sends cursor-up OUTSIDE sync blocks (missed by v1)
• v2 fix: clamps ALL cursor-up per write call to viewport height (no sync block tracking needed)
• Ctrl+6 freeze toggle works
• git diff compatible: patches/scroll-fix.patch applied via git apply -C0, fallback to string injection
• Marketplace install: /plugin install scroll-fix@cruzlauroiii-plugins
• Added to marketplace.json

[jancbeck]

@Anthropic please fix this upstream, I don't want to install a minified JS patch just so I can have long sessions in Claude Code

[nullbio]

@ashwin-ant

[nikicat]

Bug report: plugin hangs all child Node.js processes

The scroll-fix.cjs plugin, when loaded via NODE_OPTIONS="--require .../scroll-fix.cjs", causes every child Node.js process to hang indefinitely.

Root cause

The setTimeout on line 47 fires after 2 seconds and attaches a process.stdin.on("data", ...) listener. This listener keeps the Node.js event loop alive. Since NODE_OPTIONS is inherited by all child processes, tools like node-gyp-build, del-cli, and any lifecycle script spawned by npm/pnpm will load the plugin, attach the stdin listener, and never exit.

Impact

pnpm install (and likely npm install) hangs during lifecycle script execution. The parent package manager waits for child processes that will never terminate.

Suggested fix

unref() both the timeout and stdin so they don't prevent natural process exit:

var _t = setTimeout(function () {
    try {
        process.stdin.on("data", function (d) { ... });
        process.stdin.unref();
    } catch (e) {}
}, 2000);
_t.unref();

Or guard against non-interactive contexts entirely (e.g. skip when !process.stdout.isTTY).

[jwhitcraft]

Even with the patch installed, i'm still getting some random flashes, iterm2 with tmux. It's fine in my VSCode Terminal without tmux.

The flashes seems less sporadic as they are with out the patch.

[cruzlauroiii]

Currently i'm using the hotkey ctrl + 6 to scroll up and toggle when im finished, i will toggle.

…

On Thu, Mar 19, 2026 at 11:22 PM Jon Whitcraft ***@***.***> wrote: *jwhitcraft* left a comment (anthropics/claude-code#35683) <#35683 (comment)> Even with the patch installed, i'm still getting some random flashes, iterm2 with tmux. It's fine in my VSCode Terminal without tmux. The flashes seems less sporadic as they are with out the patch. — Reply to this email directly, view it on GitHub <#35683 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGJTFYJMZPJCXEUJBD7CPAL4RQGCFAVCNFSM6AAAAACWWBDKAGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAOJQHEYDENJVGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[nullbio]

Still broken as of v2.1.81:

#36582
#35403
#36816
#35683
#33814
#34845
#33367
#34400
#826
#36621
#36128
#35766
#34242
#18299