Fix: separate scrollIntoView from click in open_header_menu to drain scroll events

Combining scrollIntoView+click in a single evaluate call caused sporadic
failures in Firefox and Chromium: browsers dispatch scroll events from
scrollIntoView asynchronously (200 ms+ after the call), so they arrived
after the menu opened and after our 150 ms React scroll-to-close guard
expired — immediately closing the menu.

Splitting into two evaluate calls with a 300 ms wait between them ensures
all scroll events fire and drain before the menu opens, so none can trigger
the close listener.

Made-with: Cursor

Author: mayagbarnes

e2e_playwright/pivot_table_interactions_test.py

@@ -106,17 +106,24 @@ def open_header_menu(page: Page, trigger_locator, menu_test_id: str):
     opening the menu.  The trigger button is hidden at rest (opacity: 0) so we
     check it is attached rather than visible, and click via JS to bypass
     Playwright's visibility check.
+
+    Scroll and click are intentionally separated by a short wait.  Even with
+    ``behavior:'instant'``, browsers dispatch scroll events asynchronously — in
+    Firefox and Chromium they can fire 200 ms+ after the scrollIntoView call.
+    Our React scroll-to-close listener has a 150 ms grace period after the menu
+    opens, but if the scroll event arrives later than that it closes the menu
+    immediately.  By scrolling first, waiting for those events to drain, and
+    only then clicking to open the menu, we ensure no scroll events are
+    in-flight when the listener registers.
     """
     expect(trigger_locator).to_be_attached(timeout=5000)
     menu = page.get_by_test_id(menu_test_id)
     for attempt in range(2):
         trigger_locator.evaluate(
-            # behavior:'instant' ensures the scroll completes synchronously before
-            # click() fires. Without it, smooth-scroll animation events can arrive
-            # after the menu opens and trigger our capture-phase scroll-to-close
-            # listener, closing the menu immediately after it appears.
-            "el => { el.scrollIntoView({ block: 'center', inline: 'nearest', behavior: 'instant' }); el.click(); }"
+            "el => el.scrollIntoView({ block: 'center', inline: 'nearest', behavior: 'instant' })"
         )
+        page.wait_for_timeout(300)  # let scroll events drain before opening menu
+        trigger_locator.evaluate("el => el.click()")
         try:
             expect(menu).to_be_visible(timeout=5000)
             return menu