diff --git a/packages/ui/src/__tests__/session-history-multi-select.test.tsx b/packages/ui/src/__tests__/session-history-multi-select.test.tsx
index 4f5ed3c679..adba3a3bc1 100644
--- a/packages/ui/src/__tests__/session-history-multi-select.test.tsx
+++ b/packages/ui/src/__tests__/session-history-multi-select.test.tsx
@@ -76,13 +76,13 @@ function installDomStubs(window: ReturnType<typeof parseHTML>['window']): void {
  */
 function pointerEvent(
   window: ReturnType<typeof parseHTML>['window'],
-  type: 'click' | 'contextmenu',
+  type: 'click' | 'contextmenu' | 'pointerdown' | 'pointerup',
   modifiers: Record<string, unknown> = {},
 ): Event {
   const event = new window.Event(type, { bubbles: true, cancelable: true });
   Object.assign(event, {
     detail: 1,
-    button: type === 'contextmenu' ? 2 : 0,
+    button: type === 'contextmenu' || type.startsWith('pointer') ? 2 : 0,
     metaKey: false,
     ctrlKey: false,
     shiftKey: false,
@@ -129,6 +129,8 @@ interface Harness {
   archives: number;
   document: Document;
   clickRow(sessionId: string, modifiers?: Record<string, unknown>): Promise<void>;
+  beginRightClickRow(sessionId: string): Promise<boolean>;
+  endRightClickRow(sessionId: string): Promise<void>;
   rightClickRow(sessionId: string): Promise<boolean>;
   openRowMenu(sessionId: string): Promise<void>;
   clickMenuItem(index: number): Promise<void>;
@@ -264,15 +266,32 @@ async function mount(
         rowButton(sessionId).dispatchEvent(pointerEvent(window, 'click', modifiers));
       });
     },
-    rightClickRow: async (sessionId) => {
+    beginRightClickRow: async (sessionId) => {
       const event = pointerEvent(window, 'contextmenu');
       await act(() => {
+        rowButton(sessionId).dispatchEvent(pointerEvent(window, 'pointerdown'));
         rowButton(sessionId).dispatchEvent(event);
       });
       // Whether the rail claimed the press. Unclaimed, it goes on to the native
       // menu, which is the whole answer for a row the rail cannot act on.
       return event.defaultPrevented;
     },
+    endRightClickRow: async (sessionId) => {
+      await act(async () => {
+        rowButton(sessionId).dispatchEvent(pointerEvent(window, 'pointerup'));
+        await new Promise((resolve) => window.setTimeout(resolve, 0));
+      });
+    },
+    rightClickRow: async (sessionId) => {
+      const event = pointerEvent(window, 'contextmenu');
+      await act(async () => {
+        rowButton(sessionId).dispatchEvent(pointerEvent(window, 'pointerdown'));
+        rowButton(sessionId).dispatchEvent(event);
+        rowButton(sessionId).dispatchEvent(pointerEvent(window, 'pointerup'));
+        await new Promise((resolve) => window.setTimeout(resolve, 0));
+      });
+      return event.defaultPrevented;
+    },
     openRowMenu: async (sessionId) => {
       const trigger = document.querySelector(
         `[data-session-id="${sessionId}"] .maka-session-row-action button`,
@@ -520,8 +539,16 @@ test('right-clicking a pickable row opens its menu', async () => {
   // right-click cannot drift into two lists of items that disagree.
   const harness = await mount({ selectedIds: ['b'] });
   try {
-    const prevented = await harness.rightClickRow('b');
+    const prevented = await harness.beginRightClickRow('b');
     assert.equal(prevented, true);
+    assert.equal(
+      harness.document
+        .querySelector('[data-session-id="b"] .maka-session-row-action')
+        ?.getAttribute('data-menu-open'),
+      null,
+      'the unfinished secondary-button gesture must not light-dismiss the menu it opens',
+    );
+    await harness.endRightClickRow('b');
     assert.equal(
       harness.document
         .querySelector('[data-session-id="b"] .maka-session-row-action')
diff --git a/packages/ui/src/session-history-list.tsx b/packages/ui/src/session-history-list.tsx
index 02e53643a3..b85529633f 100644
--- a/packages/ui/src/session-history-list.tsx
+++ b/packages/ui/src/session-history-list.tsx
@@ -188,8 +188,43 @@ export function SessionHistoryList() {
   const selection = useSessionRailSelection();
   const locale = useUiLocale();
   const listRef = useRef<HTMLDivElement>(null);
+  const secondaryPointerDownRef = useRef(false);
+  const pendingContextMenuTriggerRef = useRef<HTMLElement | null>(null);
   const commands = selection?.commands;
 
+  useEffect(() => {
+    function handlePointerDown(event: PointerEvent) {
+      if (event.button === 2) secondaryPointerDownRef.current = true;
+    }
+
+    function handlePointerUp(event: PointerEvent) {
+      if (event.button !== 2) return;
+      secondaryPointerDownRef.current = false;
+      const trigger = pendingContextMenuTriggerRef.current;
+      pendingContextMenuTriggerRef.current = null;
+      // Run after the pointerup dispatch and its native light-dismiss default
+      // action have both completed. Opening inside this listener is still too
+      // early: the default action would dismiss the newly opened popover.
+      window.setTimeout(() => trigger?.click(), 0);
+    }
+
+    function cancelPendingContextMenu() {
+      secondaryPointerDownRef.current = false;
+      pendingContextMenuTriggerRef.current = null;
+    }
+
+    document.addEventListener('pointerdown', handlePointerDown, { capture: true });
+    document.addEventListener('pointerup', handlePointerUp, { capture: true });
+    document.addEventListener('pointercancel', cancelPendingContextMenu, { capture: true });
+    window.addEventListener('blur', cancelPendingContextMenu);
+    return () => {
+      document.removeEventListener('pointerdown', handlePointerDown, { capture: true });
+      document.removeEventListener('pointerup', handlePointerUp, { capture: true });
+      document.removeEventListener('pointercancel', cancelPendingContextMenu, { capture: true });
+      window.removeEventListener('blur', cancelPendingContextMenu);
+    };
+  }, []);
+
   /**
    * The rail's rendered order, read from the DOM at the moment of a click.
    *
@@ -280,6 +315,15 @@ export function SessionHistoryList() {
     const trigger = row.querySelector<HTMLElement>('.maka-session-row-action button');
     event.preventDefault();
     adoptForMenu(sessionId);
+    // Chromium fires `contextmenu` before the secondary-button pointerup on
+    // macOS. Opening a light-dismiss popover here lets that unfinished press
+    // dismiss the new menu as soon as the button is released. Other platforms
+    // may deliver `contextmenu` after pointerup, and keyboard invocations have
+    // no secondary press, so only defer while that pointer is observably down.
+    if (event.button === 2 && secondaryPointerDownRef.current) {
+      pendingContextMenuTriggerRef.current = trigger;
+      return;
+    }
     // Opening the menu re-enters `handleListClickCapture` with a synthetic
     // click, so the adoption is dispatched twice — harmless only because both
     // of its branches are idempotent: `replace` sets the same one row, and