diff --git a/docs/architecture.md b/docs/architecture.md
index b9a1f75..fd75a8f 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -218,10 +218,13 @@ component; tokens → `ui/src/styles.css`.
   skip, overwrite dialog with all/none batch modes).
 - `settings.service.ts` — one signal per setting; **imperative apply pattern**
   (`applyTheme/DarkTone/Accent` set `data-*` attributes on `<html>`;
-  `applyUiScale` sets its inline `font-size`); `applyAll` also serves the `settingsChanged` broadcast so editor
-  and manager windows restyle live (they render no settings UI, so no
-  persist echo). New setting = five touches here + types.ts (backend merges
-  automatically).
+  `applyUiScale` sets its inline `font-size`); `applyAll` also serves the
+  `settingsChanged` broadcast, so every window follows a save made in any
+  other. All three window RPCs serve `saveSettings` (editor and manager windows
+  save too — the scale shortcuts); bun's `settingsSaved()` in index.ts runs the
+  side effects once and rebroadcasts to every window **except the sender**, so
+  there is no echo to fight a held Cmd+. `applyAll` never persists. New setting
+  = five touches here + types.ts (backend merges automatically).
 - `focus.service.ts` — dependency-free `tick`/`bump()`; dialogs bump it, the
   main window's panels listen. Exists so dialogs don't inject PanelsService
   (whose constructor spawns a workspace — fatal in secondary windows).
diff --git a/docs/gotchas.md b/docs/gotchas.md
index b648a5d..7b3917c 100644
--- a/docs/gotchas.md
+++ b/docs/gotchas.md
@@ -210,6 +210,12 @@ touching the adjacent code.
 - Settings: the backend spread-merges (`{...DEFAULT_SETTINGS, ...data}`) so
   new keys auto-default, but the UI SettingsService reads field-by-field —
   a new setting silently stays at default until wired in all five spots.
+- **Every window's RPC must serve `saveSettings`.** The scale shortcuts
+  shipped in editor and manager windows while only the main RPC served it:
+  the request went unanswered, the change applied locally, and main's next
+  broadcast snapped it back. All three factories now share
+  `saveSettingsHandler`, and `settingsSaved()` in index.ts rebroadcasts to
+  every window but the sender — an echo would drag a held Cmd+ backwards.
 - The editor draft mirror sends full content per tick (2 MB cap upstream);
   don't shrink the 400 ms debounce.
 - `panel.touched` gates localDir auto-navigation; `connectToken` guards
diff --git a/src/bun/editor-windows.ts b/src/bun/editor-windows.ts
index f6cb574..f6ef3e1 100644
--- a/src/bun/editor-windows.ts
+++ b/src/bun/editor-windows.ts
@@ -33,6 +33,8 @@ export interface EditorWindowsDeps {
 	mainFrame: () => { x: number; y: number };
 	/** Late-bound senders targeting the MAIN window's webview. */
 	notifyMain: { pathRefresh: (info: { sessionId: string; dir: string }) => void };
+	/** An editor saved settings; `key` identifies it so the rebroadcast skips it. */
+	onSettingsSaved: (settings: AppSettings, key: string) => void;
 }
 
 /**
@@ -77,6 +79,7 @@ export class EditorWindows {
 					record.suppressPrompt = true;
 					record.win?.close();
 				},
+				onSettingsSaved: (next) => this.deps.onSettingsSaved(next, key),
 			},
 		);
 
@@ -165,8 +168,11 @@ export class EditorWindows {
 		});
 	}
 
-	broadcastSettings(settings: AppSettings): void {
-		this.windows.forEach((rec) => rec.rpc.send.settingsChanged({ settings }));
+	/** `exceptKey`: the editor that saved — it already shows the new values. */
+	broadcastSettings(settings: AppSettings, exceptKey?: string): void {
+		this.windows.forEach((rec, key) => {
+			if (key !== exceptKey) rec.rpc.send.settingsChanged({ settings });
+		});
 	}
 
 	private baseTitle(ctx: EditorOpenContext): string {
diff --git a/src/bun/index.ts b/src/bun/index.ts
index 0181671..728ba21 100644
--- a/src/bun/index.ts
+++ b/src/bun/index.ts
@@ -92,6 +92,7 @@ const editors = new EditorWindows({
 	currentSettings: () => currentSettings,
 	mainFrame: () => win.getFrame(),
 	notifyMain: { pathRefresh: (info) => rpc.send.pathRefresh(info) },
+	onSettingsSaved: (s, key) => settingsSaved(s, { editor: key }),
 });
 const manager = new ManagerWindow({
 	store,
@@ -105,19 +106,30 @@ const manager = new ManagerWindow({
 		menuAction: (info) => rpc.send.menuAction(info),
 	},
 	rebuildMenu: () => void applyApplicationMenu(store),
+	onSettingsSaved: (s) => settingsSaved(s, "manager"),
 });
 
 events.openEditor = (ctx) => editors.open(ctx);
-events.settingsChanged = (s) => {
+/**
+ * Every settings save lands here, whichever window made it (editor and manager
+ * windows save too — the scale shortcuts): side effects run once, then every
+ * OTHER window follows. The sender is skipped — it already shows the new
+ * values, and an echo arriving behind a newer local change (a held Cmd+) would
+ * drag it backwards.
+ */
+function settingsSaved(s: AppSettings, sender: "main" | "manager" | { editor: string }): void {
+	engine.setConcurrency(effectiveConcurrency(s));
 	const localeChanged = s.locale !== currentSettings.locale;
 	currentSettings = s; // future windows' preloads bake the fresh theme
 	if (localeChanged) {
 		setBackendLocale(s.locale);
 		void applyApplicationMenu(store); // relabel the native menu in the new language
 	}
-	editors.broadcastSettings(s);
-	manager.broadcastSettings(s);
-};
+	if (sender !== "main") rpc.send.settingsChanged({ settings: s });
+	if (sender !== "manager") manager.broadcastSettings(s);
+	editors.broadcastSettings(s, typeof sender === "object" ? sender.editor : undefined);
+}
+events.settingsChanged = (s) => settingsSaved(s, "main");
 events.openConnectionManager = () => manager.open();
 
 function showAbout(): void {
diff --git a/src/bun/manager-window.ts b/src/bun/manager-window.ts
index ccec9c8..db0b76d 100644
--- a/src/bun/manager-window.ts
+++ b/src/bun/manager-window.ts
@@ -24,6 +24,8 @@ export interface ManagerWindowDeps {
 	};
 	/** Rebuilds the native app menu after store changes. */
 	rebuildMenu: () => void;
+	/** The manager saved settings — rebroadcast them to every other window. */
+	onSettingsSaved: (settings: AppSettings) => void;
 }
 
 /**
@@ -70,6 +72,7 @@ export class ManagerWindow {
 					this.close();
 				},
 				onClose: () => this.close(),
+				onSettingsSaved: (next) => this.deps.onSettingsSaved(next),
 			},
 		);
 
diff --git a/src/bun/rpc-handlers.ts b/src/bun/rpc-handlers.ts
index 3880579..fbf491c 100644
--- a/src/bun/rpc-handlers.ts
+++ b/src/bun/rpc-handlers.ts
@@ -1,6 +1,6 @@
 import { BrowserView, Updater, Utils } from "electrobun/bun";
 import type { AppRPC, EditorOpenContext } from "../shared/rpc";
-import { effectiveConcurrency, type AppSettings, type Result } from "../shared/types";
+import type { AppSettings, Result } from "../shared/types";
 import { readFileText, writeFileText, type EditManager } from "./edits";
 import { listLocalDrives } from "./fs/local";
 import type { SessionRegistry } from "./fs/registry";
@@ -99,6 +99,22 @@ function connectionStoreHandlers(store: ConnectionStore, onChanged: () => void)
 	};
 }
 
+/**
+ * saveSettings for every window kind: persist, then hand the new object to the
+ * composition root (index.ts), which applies the side effects once and
+ * rebroadcasts to every OTHER window. Known ceiling: whole-object writes — two
+ * windows saving in the same instant, the later one wins. Upgrade path: send a
+ * patch and merge it bun-side.
+ */
+const saveSettingsHandler =
+	(store: SettingsStore, onSaved: (next: AppSettings) => void) =>
+	({ settings: next }: { settings: AppSettings }) =>
+		wrap(async () => {
+			await store.save(next);
+			onSaved(next);
+			return {};
+		});
+
 const pickKeyFileHandler = () =>
 	wrap(async () => {
 		const { homedir } = await import("node:os");
@@ -224,13 +240,7 @@ export function createAppRPC({
 				// ---- settings ----
 				getSettings: () => wrap(async () => ({ settings: await settings.load() })),
 
-				saveSettings: ({ settings: next }) =>
-					wrap(async () => {
-						await settings.save(next);
-						engine.setConcurrency(effectiveConcurrency(next));
-						events.settingsChanged(next);
-						return {};
-					}),
+				saveSettings: saveSettingsHandler(settings, (next) => events.settingsChanged(next)),
 
 				// ---- file editing ----
 				readFile: ({ sessionId, path }) =>
@@ -347,6 +357,8 @@ export interface EditorRpcHooks {
 	onSaved: () => void;
 	/** Webview resolved its dirty prompt: close without the native fallback. */
 	onCloseConfirmed: () => void;
+	/** This window saved settings (e.g. the scale shortcuts) — rebroadcast them. */
+	onSettingsSaved: (next: AppSettings) => void;
 }
 
 /**
@@ -368,6 +380,7 @@ export function createEditorRPC(
 					})),
 
 				getSettings: () => wrap(async () => ({ settings: await deps.settings.load() })),
+				saveSettings: saveSettingsHandler(deps.settings, hooks.onSettingsSaved),
 
 				editorSave: ({ content }) =>
 					wrap(async () => {
@@ -397,6 +410,8 @@ export interface ManagerRpcHooks {
 	onConnect: (id: string) => void;
 	onOpenStack: (id: string) => void;
 	onClose: () => void;
+	/** This window saved settings (e.g. the scale shortcuts) — rebroadcast them. */
+	onSettingsSaved: (next: AppSettings) => void;
 }
 
 /** RPC for the single connection-manager window (per-window instance). */
@@ -411,6 +426,7 @@ export function createManagerRPC(
 				...connectionStoreHandlers(deps.store, hooks.onChanged),
 				pickKeyFile: pickKeyFileHandler,
 				getSettings: () => wrap(async () => ({ settings: await deps.settings.load() })),
+				saveSettings: saveSettingsHandler(deps.settings, hooks.onSettingsSaved),
 
 				managerConnect: ({ id }) =>
 					wrap(async () => {