diff --git a/packages/app/e2e/regression/tabs.spec.ts b/packages/app/e2e/regression/tabs.spec.ts
index 17908249d01..46d6ab7332a 100644
--- a/packages/app/e2e/regression/tabs.spec.ts
+++ b/packages/app/e2e/regression/tabs.spec.ts
@@ -463,6 +463,45 @@ for (const [window, fullscreen, start] of [
   })
 }
 
+// macOS 26 traffic lights sit 14px down and are 14px tall. With vertical tabs the channel icon goes below them, over
+// Home's icon. A fullscreen window has no traffic lights, so the icon stays in the header beside the sidebar toggle.
+for (const [window, fullscreen] of [
+  ["windowed", false],
+  ["fullscreen", true],
+] as const) {
+  test(`sidebar channel icon sits below the macOS traffic lights (${window})`, async ({ page }) => {
+    await mockWorkspace(page, {
+      name: "Tabs",
+      sessions: [a],
+      seed: { settings: { appearance: { tabLayout: "vertical" } } },
+    })
+    await page.goto(
+      `/e2e/utils/macos-window.html?${new URLSearchParams({ server: SERVER, route: "/", fullscreen: String(fullscreen) })}`,
+    )
+    const sidebar = page.locator('[data-slot="vertical-tabs-sidebar"]')
+    const indicator = sidebar.locator('[data-slot="channel-indicator"]')
+    await expect(indicator).toBeVisible()
+
+    const icon = await indicator.boundingBox()
+    const toggle = await sidebar.getByRole("button", { name: "Toggle sidebar", exact: true }).boundingBox()
+    const home = await sidebar.getByRole("button", { name: "Home", exact: true }).boundingBox()
+    const homeIcon = await sidebar.getByRole("button", { name: "Home", exact: true }).locator("svg").boundingBox()
+
+    if (!icon || !toggle || !home || !homeIcon) throw new Error("sidebar header has no bounding boxes")
+
+    if (fullscreen) {
+      expect(icon.y + icon.height / 2).toBe(toggle.y + toggle.height / 2)
+      return
+    }
+
+    expect(icon.y).toBeGreaterThan(14 + 14)
+    expect(icon.x + icon.width / 2).toBe(homeIcon.x + homeIcon.width / 2)
+    expect(icon.y + icon.height).toBeLessThan(home.y)
+    // The toggle keeps the session header's center line beside the icon.
+    expect(toggle.y + toggle.height / 2).toBe(32)
+  })
+}
+
 test("vertical tab gaps hover and select the nearest row", async ({ page }) => {
   await mockWorkspace(page, {
     name: "Tabs",
diff --git a/packages/app/src/shell/titlebar/titlebar.tsx b/packages/app/src/shell/titlebar/titlebar.tsx
index c34d89014c8..4dcafa804a3 100644
--- a/packages/app/src/shell/titlebar/titlebar.tsx
+++ b/packages/app/src/shell/titlebar/titlebar.tsx
@@ -114,6 +114,7 @@ export function Titlebar(props: { verticalTabs?: { mount?: HTMLElement } }) {
   const titlebarItems = useTitlebarItems()
   const hideVerticalTitlebar = createMemo(() => !!props.verticalTabs && !windows())
   const homeInSidebarHeader = () => !windows() && !macTrafficLights() && !channelIndicatorVisible
+  const channelIndicatorBelowTrafficLights = () => macTrafficLights() && channelIndicatorVisible
 
   const back = () => {
     const next = backPath(history)
@@ -782,12 +783,15 @@ export function Titlebar(props: { verticalTabs?: { mount?: HTMLElement } }) {
                           >
                             <Show when={!windows()}>
                               {/* Shares the session header's 48px center line. Without traffic lights or a channel
-                                  icon, Home fills the start so the row doesn't leave an empty band. */}
+                                  icon, Home fills the start so the row doesn't leave an empty band. With both, the
+                                  channel icon goes under the traffic lights and the row grows only by what it needs. */}
                               <div
                                 class="flex w-full shrink-0 gap-2"
                                 classList={{
                                   "items-start pt-2.5": homeInSidebarHeader(),
-                                  "mb-2 h-12 items-center": !homeInSidebarHeader(),
+                                  "mb-2 h-12 items-center":
+                                    !homeInSidebarHeader() && !channelIndicatorBelowTrafficLights(),
+                                  "mb-2 items-start": channelIndicatorBelowTrafficLights(),
                                 }}
                                 style={{
                                   "min-height": macVerticalTabs()
@@ -799,23 +803,36 @@ export function Titlebar(props: { verticalTabs?: { mount?: HTMLElement } }) {
                                 <Show when={macTrafficLights()}>
                                   {/* The sidebar's 10px start padding already covers part of the traffic lights. */}
                                   <div
-                                    class="shrink-0"
-                                    style={{ width: `calc(${macTrafficLightsBaseWidth / zoom()}px - 10px)` }}
-                                    aria-hidden="true"
-                                  />
+                                    class="flex shrink-0"
+                                    style={{
+                                      width: `calc(${macTrafficLightsBaseWidth / zoom()}px - 10px)`,
+                                      "padding-top": channelIndicatorBelowTrafficLights()
+                                        ? `${macTrafficLightsTopClearance / zoom()}px`
+                                        : undefined,
+                                    }}
+                                  >
+                                    <ChannelIndicator sidebar />
+                                  </div>
                                 </Show>
                                 <Show
                                   when={homeInSidebarHeader()}
                                   fallback={
                                     <>
-                                      <ChannelIndicator sidebar />
+                                      <Show when={!macTrafficLights()}>
+                                        <ChannelIndicator sidebar />
+                                      </Show>
                                       <div class="flex-1" />
                                     </>
                                   }
                                 >
                                   <div class="min-w-0 flex-1">{homeButton(true)}</div>
                                 </Show>
-                                <SidebarToggle />
+                                <div
+                                  class="flex shrink-0"
+                                  classList={{ "mt-2.5": channelIndicatorBelowTrafficLights() }}
+                                >
+                                  <SidebarToggle />
+                                </div>
                               </div>
                             </Show>
                             <Show when={!homeInSidebarHeader()}>{homeButton(true)}</Show>