diff --git a/moli-renderer-v8/src/context_bootstrap/window_accessors/helpers.rs b/moli-renderer-v8/src/context_bootstrap/window_accessors/helpers.rs
index 26a1d871d2..e83f16e785 100644
--- a/moli-renderer-v8/src/context_bootstrap/window_accessors/helpers.rs
+++ b/moli-renderer-v8/src/context_bootstrap/window_accessors/helpers.rs
@@ -48,6 +48,19 @@ pub(in crate::context_bootstrap) fn window_child_context_handle<'s>(
     if marked_handle.is_some() {
         return marked_handle;
     }
+    // A callback can run promise reactions from another realm before its
+    // legacy dispatch marker is restored. The holder's native realm remains
+    // authoritative for WindowProperties, including a top-level holder.
+    if let Some(context) = receiver.get_creation_context(scope)
+        && let Some(host_ptr) = context_host_ptr_from_context_slot(context)
+        && let Some(identity) =
+            unsafe { &*host_ptr }.window_execution_context_identity_for_access_check(context)
+    {
+        return unsafe { &*host_ptr }
+            .window_execution_context_identity_is_current(identity)
+            .then(|| identity.dispatch_scope().child_window())
+            .flatten();
+    }
     if let Some(handle) = crate::native_bridge::active_child_window_handle(scope) {
         if receiver_is_current_global {
             return Some(handle);
@@ -76,22 +89,7 @@ pub(in crate::context_bootstrap) fn window_child_context_handle<'s>(
         }
     }
 
-    // WindowProperties is a per-realm prototype-chain object rather than the
-    // global proxy, so it has no child-handle marker of its own. Resolve its
-    // native Window identity through the creation context, mirroring Blink's
-    // native DOMWindow association on WindowProperties.
-    let receiver_context = receiver.get_creation_context(scope)?;
-    let host_ptr = context_host_ptr_from_context_slot(receiver_context)?;
-    let host = unsafe { &*host_ptr };
-    let identity = host.window_execution_context_identity_for_access_check(receiver_context)?;
-    if !host.window_execution_context_identity_is_current(identity) {
-        return None;
-    }
-    match identity.dispatch_scope() {
-        crate::native_bridge::OwnerDispatchScope::Child(handle) => Some(handle),
-        crate::native_bridge::OwnerDispatchScope::Top
-        | crate::native_bridge::OwnerDispatchScope::LightweightPopup(_) => None,
-    }
+    None
 }
 
 pub(crate) fn window_host_ptr(
diff --git a/moli-renderer-v8/src/script_vm/tests/dom_elements/dom_surface.rs b/moli-renderer-v8/src/script_vm/tests/dom_elements/dom_surface.rs
index 5f01fecaa6..bae007532e 100644
--- a/moli-renderer-v8/src/script_vm/tests/dom_elements/dom_surface.rs
+++ b/moli-renderer-v8/src/script_vm/tests/dom_elements/dom_surface.rs
@@ -14524,3 +14524,36 @@ fn child_browsing_context_lookup_tolerates_document_handle_cycle() {
         Some(handle)
     );
 }
+
+#[test]
+fn window_named_access_uses_its_realm_during_child_history_callbacks() {
+    let mut vm = new_storage_test_vm("https://joint-history.test/parent");
+    vm.eval(
+        r#"
+      const frame = document.createElement('iframe');
+      frame.id = 'topFrame';
+      frame.srcdoc = '<p id="childOnly">child</p>';
+      (document.body || document.documentElement || document).appendChild(frame);
+    "#,
+    )
+    .unwrap();
+    vm.drain_pending_child_frame_work_for_test();
+    let child = vm
+        ._context_host
+        .borrow()
+        .child_browsing_context_handles_in_document_order()[0];
+    let context = &vm.page_default_context as *const v8::Global<v8::Context>;
+    vm.with_context_scope_by_ptr(context, |scope, _| {
+        crate::native_bridge::enter_active_child_window_scope(scope, Some(child));
+        Ok(())
+    })
+    .unwrap();
+    let result =
+        vm.eval("[topFrame.id, typeof childOnly, frame.contentWindow.childOnly.id].join('|')");
+    vm.with_context_scope_by_ptr(context, |scope, _| {
+        crate::native_bridge::enter_active_child_window_scope(scope, None);
+        Ok(())
+    })
+    .unwrap();
+    assert_eq!(result.unwrap(), "topFrame|undefined|childOnly");
+}