diff --git a/windows/tauri/src/features/layout/components/sidebar/main-sidebar.tsx b/windows/tauri/src/features/layout/components/sidebar/main-sidebar.tsx
index 9168ef4b9..ee13aa2a9 100644
--- a/windows/tauri/src/features/layout/components/sidebar/main-sidebar.tsx
+++ b/windows/tauri/src/features/layout/components/sidebar/main-sidebar.tsx
@@ -26,6 +26,7 @@ import {
   getProjectSnapDuration,
   getProjectSwipeBounds,
 } from "@/features/layout/utils/project-carousel";
+import { shouldShowProjectSwitcher } from "@/features/layout/utils/project-switcher";
 import type { SidebarView } from "@/features/layout/utils/sidebar-pane-utils";
 import { useSettingsStore } from "@/features/settings/stores/settings.store";
 import { useBufferStore } from "@/features/editor/stores/buffer.store";
@@ -154,6 +155,10 @@ export const SidebarActivityRail = memo(({ expanded = false }: SidebarActivityRa
     projectCarouselDirection < 0 && carouselTargetProject ? carouselTargetProject : previousProject;
   const renderedNextProject =
     projectCarouselDirection > 0 && carouselTargetProject ? carouselTargetProject : nextProject;
+  const projectSwitcherVisible = shouldShowProjectSwitcher(
+    showActivityRailProjectSwitcher,
+    openFoldersInNewWindow,
+  );
   const switchToProject = useFileSystemStore((state) => state.switchToProject);
   const isSwitchingProject = useFileSystemStore((state) => state.isSwitchingProject);
   const handleSidebarViewChange = (view: typeof activeSidebarView) => {
@@ -607,7 +612,7 @@ export const SidebarActivityRail = memo(({ expanded = false }: SidebarActivityRa
       >
         {isBoundaryPanel ? null : (
           <>
-            {showActivityRailProjectSwitcher ? (
+            {projectSwitcherVisible ? (
               <SidebarProjectSwitcher
                 expanded={expanded}
                 project={project}
diff --git a/windows/tauri/src/features/layout/utils/project-switcher.test.ts b/windows/tauri/src/features/layout/utils/project-switcher.test.ts
new file mode 100644
index 000000000..9ab16c5ab
--- /dev/null
+++ b/windows/tauri/src/features/layout/utils/project-switcher.test.ts
@@ -0,0 +1,17 @@
+import { describe, expect, test } from "bun:test";
+import { shouldShowProjectSwitcher } from "./project-switcher";
+
+describe("project switcher visibility", () => {
+  test("hides the activity-bar switcher when projects open in new windows", () => {
+    expect(shouldShowProjectSwitcher(true, true)).toBe(false);
+  });
+
+  test("shows the activity-bar switcher when in-window switching is enabled", () => {
+    expect(shouldShowProjectSwitcher(true, false)).toBe(true);
+  });
+
+  test("respects the user's project switcher visibility setting", () => {
+    expect(shouldShowProjectSwitcher(false, false)).toBe(false);
+    expect(shouldShowProjectSwitcher(false, true)).toBe(false);
+  });
+});
diff --git a/windows/tauri/src/features/layout/utils/project-switcher.ts b/windows/tauri/src/features/layout/utils/project-switcher.ts
new file mode 100644
index 000000000..71e948b2f
--- /dev/null
+++ b/windows/tauri/src/features/layout/utils/project-switcher.ts
@@ -0,0 +1,6 @@
+export function shouldShowProjectSwitcher(
+  showProjectSwitcher: boolean,
+  openFoldersInNewWindow: boolean,
+) {
+  return showProjectSwitcher && !openFoldersInNewWindow;
+}