diff --git a/moli-renderer-v8/src/context_bootstrap/navigation_window.rs b/moli-renderer-v8/src/context_bootstrap/navigation_window.rs
index 250f1b572c..707e686053 100644
--- a/moli-renderer-v8/src/context_bootstrap/navigation_window.rs
+++ b/moli-renderer-v8/src/context_bootstrap/navigation_window.rs
@@ -106,7 +106,7 @@ pub(in crate::context_bootstrap) fn child_browsing_context_handle_for_runtime_ow
         })
 }
 
-pub(super) fn runtime_window_dispatch_scope<'s>(
+pub(in crate::context_bootstrap) fn runtime_window_dispatch_scope<'s>(
     scope: &mut v8::PinScope<'s, '_>,
     window: v8::Local<'s, v8::Object>,
 ) -> Option<crate::native_bridge::OwnerDispatchScope> {
diff --git a/moli-renderer-v8/src/context_bootstrap/runtime_state.rs b/moli-renderer-v8/src/context_bootstrap/runtime_state.rs
index dd8ec8d090..ab4fd1bb8a 100644
--- a/moli-renderer-v8/src/context_bootstrap/runtime_state.rs
+++ b/moli-renderer-v8/src/context_bootstrap/runtime_state.rs
@@ -663,9 +663,23 @@ fn window_length_replaceable_getter<'s>(
         return;
     };
     let host = unsafe { &mut *host_ptr };
-    let count = child_context_handle_from_owner(scope, args.this())
-        .map(|handle| host.child_browsing_context_child_frame_count(handle))
-        .unwrap_or_else(|| host.child_browsing_context_count());
+    let document = match super::navigation_window::runtime_window_dispatch_scope(scope, args.this())
+    {
+        Some(crate::native_bridge::OwnerDispatchScope::Top) => Some(host.document_handle()),
+        Some(crate::native_bridge::OwnerDispatchScope::Child(handle)) => {
+            host.child_browsing_context_document_handle(handle)
+        }
+        Some(crate::native_bridge::OwnerDispatchScope::LightweightPopup(popup_id)) => {
+            host.lightweight_popup_document_handle(popup_id)
+        }
+        None => None,
+    };
+    let count = document
+        .map(|document| {
+            host.sync_child_browsing_context_subtree(scope, document);
+            host.child_browsing_context_count_for_document(document)
+        })
+        .unwrap_or(0);
     rv.set(v8::Number::new(scope, count as f64).into());
 }
 
diff --git a/moli-renderer-v8/src/context_bootstrap/window_accessors/child_context.rs b/moli-renderer-v8/src/context_bootstrap/window_accessors/child_context.rs
index eb71616a53..81f70afec6 100644
--- a/moli-renderer-v8/src/context_bootstrap/window_accessors/child_context.rs
+++ b/moli-renderer-v8/src/context_bootstrap/window_accessors/child_context.rs
@@ -1,5 +1,6 @@
 use super::helpers::{
-    window_child_context_handle, window_hidden_value, window_host_ptr, window_receiver,
+    window_child_context_handle, window_document_handle, window_hidden_value, window_host_ptr,
+    window_receiver,
 };
 use super::*;
 
@@ -16,11 +17,12 @@ pub(in crate::context_bootstrap) fn window_length_getter<'s>(
         return;
     };
     let runtime = unsafe { &mut *host_ptr };
-    let count = if let Some(handle) = window_child_context_handle(scope, receiver) {
-        runtime.child_browsing_context_child_frame_count(handle)
-    } else {
-        runtime.child_browsing_context_count()
-    };
+    let count = window_document_handle(scope, receiver, runtime)
+        .map(|document| {
+            runtime.sync_child_browsing_context_subtree(scope, document);
+            runtime.child_browsing_context_count_for_document(document)
+        })
+        .unwrap_or(0);
     rv.set(v8::Number::new(scope, count as f64).into());
 }
 
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 19860fa70a..7238c3eac7 100644
--- a/moli-renderer-v8/src/context_bootstrap/window_accessors/helpers.rs
+++ b/moli-renderer-v8/src/context_bootstrap/window_accessors/helpers.rs
@@ -92,6 +92,33 @@ pub(in crate::context_bootstrap) fn window_child_context_handle<'s>(
     None
 }
 
+pub(super) fn window_owner_dispatch_scope<'s>(
+    scope: &mut v8::PinScope<'s, '_>,
+    receiver: v8::Local<'s, v8::Object>,
+) -> Option<crate::native_bridge::OwnerDispatchScope> {
+    super::super::navigation_window::runtime_window_dispatch_scope(scope, receiver).or_else(|| {
+        receiver
+            .strict_equals(scope.get_current_context().global(scope).into())
+            .then_some(crate::native_bridge::OwnerDispatchScope::Top)
+    })
+}
+
+pub(super) fn window_document_handle<'s>(
+    scope: &mut v8::PinScope<'s, '_>,
+    receiver: v8::Local<'s, v8::Object>,
+    host: &JsContextHost,
+) -> Option<crate::document_runtime::DomHandle> {
+    match window_owner_dispatch_scope(scope, receiver)? {
+        crate::native_bridge::OwnerDispatchScope::Top => Some(host.document_handle()),
+        crate::native_bridge::OwnerDispatchScope::Child(handle) => {
+            host.child_browsing_context_document_handle(handle)
+        }
+        crate::native_bridge::OwnerDispatchScope::LightweightPopup(popup_id) => {
+            host.lightweight_popup_document_handle(popup_id)
+        }
+    }
+}
+
 pub(crate) fn window_host_ptr(
     scope: &mut v8::PinScope<'_, '_>,
     receiver: v8::Local<'_, v8::Object>,
diff --git a/moli-renderer-v8/src/context_bootstrap/window_accessors/interceptors.rs b/moli-renderer-v8/src/context_bootstrap/window_accessors/interceptors.rs
index e4311f9fed..084dd5bd72 100644
--- a/moli-renderer-v8/src/context_bootstrap/window_accessors/interceptors.rs
+++ b/moli-renderer-v8/src/context_bootstrap/window_accessors/interceptors.rs
@@ -1,4 +1,7 @@
-use super::helpers::{window_child_context_handle, window_host_ptr};
+use super::helpers::{
+    window_child_context_handle, window_document_handle, window_host_ptr,
+    window_owner_dispatch_scope,
+};
 use crate::native_bridge::named_access::{
     build_window_named_items_collection, window_named_item_handles,
 };
@@ -11,24 +14,34 @@ fn is_reserved_window_name(name: &str) -> bool {
 
 fn window_indexed_child_handle<'s>(
     scope: &mut v8::PinScope<'s, '_>,
-    holder: v8::Local<'s, v8::Object>,
+    receiver: v8::Local<'s, v8::Object>,
     index: u32,
 ) -> Option<(
     *mut crate::native_bridge::JsContextHost,
     crate::document_runtime::DomHandle,
+    crate::native_bridge::OwnerDispatchScope,
 )> {
-    let host_ptr = window_host_ptr(scope, holder)?;
+    let host_ptr = window_host_ptr(scope, receiver)?;
     let host = unsafe { &mut *host_ptr };
-    let handle = if let Some(parent) = window_child_context_handle(scope, holder) {
-        if let Some(document) = host.child_browsing_context_document_handle(parent) {
-            host.sync_child_browsing_context_subtree(scope, document);
-        }
-        host.child_browsing_context_child_frame_handle_by_index(parent, index as usize)
+    let owner_scope = window_owner_dispatch_scope(scope, receiver)?;
+    let document = window_document_handle(scope, receiver, host)?;
+    host.sync_child_browsing_context_subtree(scope, document);
+    let handle =
+        host.child_browsing_context_handle_by_index_for_document(document, index as usize)?;
+    Some((host_ptr, handle, owner_scope))
+}
+
+fn window_child_projection_for_owner<'s>(
+    scope: &mut v8::PinScope<'s, '_>,
+    host: &mut crate::native_bridge::JsContextHost,
+    handle: crate::document_runtime::DomHandle,
+    owner_scope: crate::native_bridge::OwnerDispatchScope,
+) -> Option<v8::Local<'s, v8::Object>> {
+    if owner_scope == crate::native_bridge::OwnerDispatchScope::Top {
+        host.child_browsing_context_window_proxy_for_top(scope, handle)
     } else {
-        host.sync_child_browsing_context_subtree(scope, host.document_handle());
-        host.child_browsing_context_handle_by_index(index as usize)
-    }?;
-    Some((host_ptr, handle))
+        host.child_browsing_context_window_wrapper(scope, handle)
+    }
 }
 
 pub(in crate::context_bootstrap) fn window_indexed_property_getter<'s>(
@@ -37,16 +50,13 @@ pub(in crate::context_bootstrap) fn window_indexed_property_getter<'s>(
     args: v8::PropertyCallbackArguments<'s>,
     mut rv: v8::ReturnValue<'_, v8::Value>,
 ) -> v8::Intercepted {
-    let holder = args.holder();
-    let Some((host_ptr, handle)) = window_indexed_child_handle(scope, holder, index) else {
+    let Some((host_ptr, handle, owner_scope)) =
+        window_indexed_child_handle(scope, args.holder(), index)
+    else {
         return v8::Intercepted::kNo;
     };
     let host = unsafe { &mut *host_ptr };
-    let window = if window_child_context_handle(scope, holder).is_none() {
-        host.child_browsing_context_window_proxy_for_top(scope, handle)
-    } else {
-        host.child_browsing_context_window_wrapper(scope, handle)
-    };
+    let window = window_child_projection_for_owner(scope, host, handle, owner_scope);
     let Some(window) = window else {
         return v8::Intercepted::kNo;
     };
@@ -72,22 +82,18 @@ pub(in crate::context_bootstrap) fn window_indexed_property_enumerator<'s>(
     args: v8::PropertyCallbackArguments<'s>,
     mut rv: v8::ReturnValue<'_, v8::Array>,
 ) {
-    let holder = args.holder();
-    let Some(host_ptr) = window_host_ptr(scope, holder) else {
+    let receiver = args.holder();
+    let Some(host_ptr) = window_host_ptr(scope, receiver) else {
         rv.set(v8::Array::new(scope, 0));
         return;
     };
     let host = unsafe { &mut *host_ptr };
-    let count = if let Some(parent) = window_child_context_handle(scope, holder) {
-        if let Some(document) = host.child_browsing_context_document_handle(parent) {
+    let count = window_document_handle(scope, receiver, host)
+        .map(|document| {
             host.sync_child_browsing_context_subtree(scope, document);
-        }
-        host.child_browsing_context_child_frame_handles(parent)
-            .len()
-    } else {
-        host.sync_child_browsing_context_subtree(scope, host.document_handle());
-        host.child_browsing_context_count()
-    };
+            host.child_browsing_context_count_for_document(document)
+        })
+        .unwrap_or(0);
     let array = serialize_v8_iter_array(scope, (0..count).map(|index| index as u32))
         .unwrap_or_else(|| v8::Array::new(scope, 0));
     rv.set(array);
@@ -99,16 +105,13 @@ pub(in crate::context_bootstrap) fn window_indexed_property_descriptor<'s>(
     args: v8::PropertyCallbackArguments<'s>,
     mut rv: v8::ReturnValue<'_, v8::Value>,
 ) -> v8::Intercepted {
-    let Some((host_ptr, handle)) = window_indexed_child_handle(scope, args.holder(), index) else {
+    let Some((host_ptr, handle, owner_scope)) =
+        window_indexed_child_handle(scope, args.holder(), index)
+    else {
         return v8::Intercepted::kNo;
     };
-    let holder = args.holder();
     let host = unsafe { &mut *host_ptr };
-    let window = if window_child_context_handle(scope, holder).is_none() {
-        host.child_browsing_context_window_proxy_for_top(scope, handle)
-    } else {
-        host.child_browsing_context_window_wrapper(scope, handle)
-    };
+    let window = window_child_projection_for_owner(scope, host, handle, owner_scope);
     let Some(window) = window else {
         return v8::Intercepted::kNo;
     };
diff --git a/moli-renderer-v8/src/native_bridge/context_host/child_frames/lookup.rs b/moli-renderer-v8/src/native_bridge/context_host/child_frames/lookup.rs
index 11f24ae3a9..8d46dab64c 100644
--- a/moli-renderer-v8/src/native_bridge/context_host/child_frames/lookup.rs
+++ b/moli-renderer-v8/src/native_bridge/context_host/child_frames/lookup.rs
@@ -18,6 +18,11 @@ impl JsContextHost {
             .len()
     }
 
+    pub(crate) fn child_browsing_context_count_for_document(&self, document: DomHandle) -> usize {
+        self.child_browsing_context_direct_frame_handles_for_document(document)
+            .len()
+    }
+
     pub(crate) fn child_browsing_context_handles_in_document_order(&self) -> Vec<DomHandle> {
         let mut handles = Vec::new();
         self.collect_child_browsing_context_handles_in_document_order_from_document(
@@ -118,22 +123,38 @@ impl JsContextHost {
             .collect()
     }
 
+    fn child_browsing_context_direct_frame_handles_for_document(
+        &self,
+        document: DomHandle,
+    ) -> Vec<DomHandle> {
+        self.child_browsing_contexts
+            .keys()
+            .copied()
+            .filter(|handle| {
+                self.dom_host().node(*handle).and_then(Node::owner_document) == Some(document)
+            })
+            .collect()
+    }
+
+    #[cfg(test)]
     pub(crate) fn child_browsing_context_handle_by_index(&self, index: usize) -> Option<DomHandle> {
-        // Window indexed/named interceptors hit this on every miss.
-        if self.child_browsing_contexts.is_empty() {
-            return None;
-        }
+        // Tests use this to inspect the global frame-tree projection rather
+        // than one Window's scoped indexed properties.
         self.top_level_child_browsing_context_handles_in_frame_tree_order()
             .into_iter()
             .nth(index)
     }
 
-    pub(crate) fn child_browsing_context_child_frame_handle_by_index(
+    pub(crate) fn child_browsing_context_handle_by_index_for_document(
         &self,
-        parent: DomHandle,
+        document: DomHandle,
         index: usize,
     ) -> Option<DomHandle> {
-        self.child_browsing_context_child_frame_handles(parent)
+        // Window indexed/named interceptors hit this on every miss.
+        if self.child_browsing_contexts.is_empty() {
+            return None;
+        }
+        self.child_browsing_context_direct_frame_handles_for_document(document)
             .into_iter()
             .nth(index)
     }
@@ -142,11 +163,9 @@ impl JsContextHost {
         &self,
         parent: DomHandle,
     ) -> Vec<DomHandle> {
-        self.child_browsing_contexts
-            .keys()
-            .copied()
-            .filter(|handle| self.child_browsing_context_parent_handle(*handle) == Some(parent))
-            .collect()
+        self.child_browsing_context_document_handle(parent)
+            .map(|document| self.child_browsing_context_direct_frame_handles_for_document(document))
+            .unwrap_or_default()
     }
 
     pub(crate) fn child_browsing_context_direct_host_handles(
diff --git a/moli-renderer-v8/src/native_bridge/context_host/popups.rs b/moli-renderer-v8/src/native_bridge/context_host/popups.rs
index 4f3e187a24..fd7c10ce8f 100644
--- a/moli-renderer-v8/src/native_bridge/context_host/popups.rs
+++ b/moli-renderer-v8/src/native_bridge/context_host/popups.rs
@@ -653,8 +653,7 @@ impl JsContextHost {
         creator_base_url: Url,
         creator_policy_container: DocumentPolicyContainer,
     ) -> Option<OpenedLightweightPopup<'s>> {
-        if opener.is_some()
-            && let Some(name) = trackable_lightweight_popup_window_name(target_name)
+        if let Some(name) = trackable_lightweight_popup_window_name(target_name)
             && let Some(popup_id) = self.lightweight_popup_window_names.get(&name).copied()
             && self.lightweight_popup_is_open(popup_id)
             && let Some(window) = self.reopen_lightweight_popup_window(
diff --git a/moli-renderer-v8/src/script_vm/tests/browser_api/misc/extracted/popup_window.rs b/moli-renderer-v8/src/script_vm/tests/browser_api/misc/extracted/popup_window.rs
index 2ffe05e8a8..3538dcecad 100644
--- a/moli-renderer-v8/src/script_vm/tests/browser_api/misc/extracted/popup_window.rs
+++ b/moli-renderer-v8/src/script_vm/tests/browser_api/misc/extracted/popup_window.rs
@@ -2901,3 +2901,103 @@ async fn lightweight_popup_external_script_redirect_final_url_obeys_csp() {
         format!("{final_script_url}|script-src-elem|enforce|true||load:true")
     );
 }
+
+#[tokio::test]
+async fn lightweight_popup_window_child_queries_stay_in_the_popup_document() {
+    let loader = ResourceRequestClient::new(&moli_fetch::FetchConfig::default()).expect("loader");
+    let mut vm =
+        new_page_task_executor_test_vm_with_loader("https://example.com/base/page.html", &loader);
+
+    let result = vm
+        .eval(
+            r#"
+(() => {
+  globalThis.__popupFrameScopeProbe = "pending";
+  const topFrame = document.createElement("iframe");
+  topFrame.name = "top-child";
+  document.body.appendChild(topFrame);
+  topFrame.contentDocument.body.innerHTML = '<p id="top-only"></p>';
+
+  const popupMarkup = `
+    <!doctype html>
+    <iframe name="popup-child" srcdoc="<p id='popup-only'></p>"></iframe>
+    <script>
+      addEventListener("load", () => {
+        const childDocument = frames[0].document;
+        opener.__popupFrameScopeProbe = JSON.stringify({
+          length: window.length,
+          name: frames[0].name,
+          popupNode: childDocument.getElementById("popup-only") !== null,
+          topNode: childDocument.getElementById("top-only") !== null
+        });
+      });
+    <\/script>
+  `;
+  open(URL.createObjectURL(new Blob([popupMarkup], { type: "text/html" })));
+  return __popupFrameScopeProbe;
+})()
+"#,
+        )
+        .expect("popup child-query scope setup should evaluate");
+
+    assert_eq!(result, "pending");
+    advance_page_task_executor_until_eval_equals(
+        &mut vm,
+        &loader,
+        "__popupFrameScopeProbe",
+        r#"{"length":1,"name":"popup-child","popupNode":true,"topNode":false}"#,
+        "popup child-query document scope",
+    )
+    .await;
+}
+
+#[tokio::test]
+async fn noopener_hyperlink_reuses_an_existing_named_popup_and_preserves_its_opener() {
+    let loader = ResourceRequestClient::new(&moli_fetch::FetchConfig::default()).expect("loader");
+    let mut vm =
+        new_page_task_executor_test_vm_with_loader("https://example.com/base/page.html", &loader);
+
+    let result = vm
+        .eval(
+            r#"
+(() => {
+  const popupName = "moli-noopener-named-target";
+  const popup = open("about:blank", popupName);
+  const targetMarkup = '<!doctype html><p id="named-target"></p>';
+  const targetUrl = URL.createObjectURL(new Blob([targetMarkup], { type: "text/html" }));
+  const link = document.createElement("a");
+  link.rel = "noopener";
+  link.target = popupName;
+  link.href = targetUrl;
+  document.body.appendChild(link);
+  globalThis.__namedNoopenerPopup = popup;
+  globalThis.__namedNoopenerTargetUrl = targetUrl;
+  link.click();
+  return String(popup.location.href === targetUrl && popup.opener === window);
+})()
+"#,
+        )
+        .expect("named noopener popup setup should evaluate");
+
+    assert_eq!(result, "true");
+    advance_page_task_executor_until_eval_equals(
+        &mut vm,
+        &loader,
+        "String(__namedNoopenerPopup.document.getElementById('named-target') !== null)",
+        "true",
+        "named noopener target navigation",
+    )
+    .await;
+
+    assert_eq!(
+        vm.eval(
+            r#"JSON.stringify({
+  openerPreserved: __namedNoopenerPopup.opener === window,
+  namePreserved: __namedNoopenerPopup.name === "moli-noopener-named-target",
+  targetCommitted: __namedNoopenerPopup.location.href === __namedNoopenerTargetUrl
+})"#,
+        )
+        .expect("named noopener popup result should evaluate"),
+        r#"{"openerPreserved":true,"namePreserved":true,"targetCommitted":true}"#
+    );
+}