Windows: Toast popup when user presses ctrl+v

[simo787c]

Summary

Introduce a dismissable toast when pressing ctrl+v on windows pointing users to natively supported and working alt+v

Windows users pasting into the Claude Code TUI via Dash hit silent data loss: Ctrl+V and Ctrl+Shift+V drop text from long pastes silently. The root cause is in our own PTY layer: on Windows/ConPTY, node-pty ignores the Socket.write() backpressure return, so writes past ~2 KB are silently discarded. Fixing that properly means chunking writes in ptyManager — real work, and we'd instead point users to already existing keybind that properly supports long text truncations and images. Claude Code handles Alt+V natively for both text and images, so the paste never traverses our broken write path.

Alt+V is a Claude Code keybinding, not a Windows OS feature — so it isn't tied to any Windows version; it works anywhere Claude Code runs (including WSL).

• It is the default for the chat:imagePaste action on Windows and WSL; macOS/Linux default that action to Ctrl+V instead. On WSL both are bound. (keybindings docs)
• Claude Code's customizable keybindings — where Alt+V is documented — require v2.1.18+.
• The Windows Alt+V image-paste fix specifically shipped in v2.1.157 (May 29, 2026), alongside the Windows 11 screenshot-paste fix and drag-from-Explorer support.
• It exists because Windows Terminal reserves Ctrl+V for text paste and intercepts it before Claude Code sees it, so Alt+V is the native alternative.

Changes

File	What
windowsPasteToast.tsx	The toast: maybeShowWindowsPasteToast() + the PasteTip card
TerminalSessionManager.ts	Fires the toast on Windows Ctrl+V; caches the isWindows platform check
settingsKeys.ts	Registers hasDismissedWindowsPasteToast so the opt-out persists

Behaviour notes

• Trigger is a pure side effect in the key handler — no preventDefault/return, so existing paste handling is untouched and Alt+V passes through unaffected.
• Windows-only, gated on getPlatform() === 'win32'. Cached at construction rather than read per keystroke.
• De-duped onto a fixed toast id, so holding Ctrl+V doesn't stack toasts.
• Dismissal is two-tier: closing the toast stays quiet for the rest of the session but nudges once more next launch; ticking "Don't show again" persists via the new setting. The reasoning is that a user who dismisses without ticking probably hasn't internalised the tip yet.
• Design mirrors the existing ports-wizard toast (PortsWizardToasts.tsx): same toast.custom card shell, icon + title + muted body, quiet opt-out on the left and the plain close on the right.

Testing

pnpm type-check passes; lint and the pre-commit hooks are green.

Verified in the running app (Windows 11): pressing Ctrl+V in a task terminal surfaces the toast. An earlier "the toast doesn't appear" report turned out to be environmental, not a code issue — a dev server from another checkout still held port 3000, so this worktree's Electron was loading the other renderer. (vite.config.ts sets server.port: 3000 without strictPort, so Vite silently falls back to 3001 while window.ts still loads localhost:3000 — a trap worth knowing if you run two Dash checkouts at once.)

Still worth a click-through before merge: the two dismissal paths — session-scoped (close/swipe, should re-nudge next launch) vs persisted (tick "Don't show again", reload, should stay gone).