diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 1cfbdef5c875..bc54c7df23e4 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -9746,6 +9746,8 @@ nsIPrincipal* nsDocShell::GetInheritedPrincipal(
       INTERNAL_LOAD_FLAGS_FORCE_ALLOW_DATA_URI));
   aLoadInfo->SetOriginalFrameSrcLoad(
       aLoadState->HasInternalLoadFlags(INTERNAL_LOAD_FLAGS_ORIGINAL_FRAME_SRC));
+  aLoadInfo->SetIsNewWindowTarget(
+      aLoadState->HasInternalLoadFlags(INTERNAL_LOAD_FLAGS_FIRST_LOAD));
 
   bool inheritAttrs = false;
   if (aLoadState->PrincipalToInherit()) {
@@ -9886,10 +9888,6 @@ nsIPrincipal* nsDocShell::GetInheritedPrincipal(
     // save true referrer for those who need it (e.g. xpinstall whitelisting)
     // Currently only http and ftp channels support this.
     props->SetPropertyAsInterface(u"docshell.internalReferrer"_ns, referrer);
-
-    if (aLoadState->HasInternalLoadFlags(INTERNAL_LOAD_FLAGS_FIRST_LOAD)) {
-      props->SetPropertyAsBool(u"docshell.newWindowTarget"_ns, true);
-    }
   }
 
   nsCOMPtr<nsICacheInfoChannel> cacheChannel(do_QueryInterface(channel));
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 44b3767a3486..a284b38cab47 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -4809,8 +4809,7 @@ ContentParent::AllocPExternalHelperAppParent(
     const uint32_t& aContentDispositionHint,
     const nsAString& aContentDispositionFilename, const bool& aForceSave,
     const int64_t& aContentLength, const bool& aWasFileChannel,
-    nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
-    const bool& aShouldCloseWindow) {
+    nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext) {
   RefPtr<ExternalHelperAppParent> parent = new ExternalHelperAppParent(
       uri, aContentLength, aWasFileChannel, aContentDisposition,
       aContentDispositionHint, aContentDispositionFilename);
@@ -4824,12 +4823,10 @@ mozilla::ipc::IPCResult ContentParent::RecvPExternalHelperAppConstructor(
     const uint32_t& aContentDispositionHint,
     const nsAString& aContentDispositionFilename, const bool& aForceSave,
     const int64_t& aContentLength, const bool& aWasFileChannel,
-    nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
-    const bool& aShouldCloseWindow) {
+    nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext) {
   BrowsingContext* context = aContext.IsDiscarded() ? nullptr : aContext.get();
   if (!static_cast<ExternalHelperAppParent*>(actor)->Init(
-          loadInfoArgs, aMimeContentType, aForceSave, aReferrer, context,
-          aShouldCloseWindow)) {
+          loadInfoArgs, aMimeContentType, aForceSave, aReferrer, context)) {
     return IPC_FAIL(this, "Init failed.");
   }
   return IPC_OK();
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index 27645238a85f..cd094f0e55d3 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -929,8 +929,7 @@ class ContentParent final : public PContentParent,
       const uint32_t& aContentDispositionHint,
       const nsAString& aContentDispositionFilename, const bool& aForceSave,
       const int64_t& aContentLength, const bool& aWasFileChannel,
-      nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
-      const bool& aShouldCloseWindow);
+      nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext);
 
   mozilla::ipc::IPCResult RecvPExternalHelperAppConstructor(
       PExternalHelperAppParent* actor, nsIURI* uri,
@@ -939,8 +938,8 @@ class ContentParent final : public PContentParent,
       const uint32_t& aContentDispositionHint,
       const nsAString& aContentDispositionFilename, const bool& aForceSave,
       const int64_t& aContentLength, const bool& aWasFileChannel,
-      nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
-      const bool& aShouldCloseWindow) override;
+      nsIURI* aReferrer,
+      const MaybeDiscarded<BrowsingContext>& aContext) override;
 
   already_AddRefed<PHandlerServiceParent> AllocPHandlerServiceParent();
 
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 181c220525e7..3162d9ae4423 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -1173,8 +1173,6 @@ parent:
     //
     // Pass true for aForceSave to always save this content to disk, regardless of
     // nsIMIMEInfo and other such influences.
-    // Pass true for aShouldCloseWindow to specify that aContext was opened specifically
-    // for this load, and should be closed once we've handled it.
     async PExternalHelperApp(nullable nsIURI uri,
                              LoadInfoArgs loadInfoArgs,
                              nsCString aMimeContentType,
@@ -1185,8 +1183,7 @@ parent:
                              int64_t aContentLength,
                              bool aWasFileChannel,
                              nullable nsIURI aReferrer,
-                             MaybeDiscardedBrowsingContext aContext,
-                             bool aShouldCloseWindow);
+                             MaybeDiscardedBrowsingContext aContext);
 
     async PHandlerService();
 
diff --git a/ipc/glue/BackgroundUtils.cpp b/ipc/glue/BackgroundUtils.cpp
index 40fae18bdeb3..e19a07776a32 100644
--- a/ipc/glue/BackgroundUtils.cpp
+++ b/ipc/glue/BackgroundUtils.cpp
@@ -596,7 +596,7 @@ nsresult LoadInfoToLoadInfoArgs(nsILoadInfo* aLoadInfo,
       aLoadInfo->GetStoragePermission(), overriddenFingerprintingSettingsArg,
       aLoadInfo->GetIsMetaRefresh(), aLoadInfo->GetLoadingEmbedderPolicy(),
       aLoadInfo->GetIsOriginTrialCoepCredentiallessEnabledForTopLevel(),
-      unstrippedURI, interceptionInfoArg);
+      unstrippedURI, interceptionInfoArg, aLoadInfo->GetIsNewWindowTarget());
 
   return NS_OK;
 }
@@ -885,7 +885,7 @@ nsresult LoadInfoArgsToLoadInfo(const LoadInfoArgs& loadInfoArgs,
       loadInfoArgs.originTrialCoepCredentiallessEnabledForTopLevel(),
       loadInfoArgs.unstrippedURI(), interceptionInfo,
       loadInfoArgs.hasInjectedCookieForCookieBannerHandling(),
-      loadInfoArgs.wasSchemelessInput());
+      loadInfoArgs.wasSchemelessInput(), loadInfoArgs.isNewWindowTarget());
 
   if (loadInfoArgs.isFromProcessingFrameAttributes()) {
     loadInfo->SetIsFromProcessingFrameAttributes();
diff --git a/netwerk/base/LoadInfo.cpp b/netwerk/base/LoadInfo.cpp
index 5ff1c5ad8b26..b4683367c1f5 100644
--- a/netwerk/base/LoadInfo.cpp
+++ b/netwerk/base/LoadInfo.cpp
@@ -691,7 +691,8 @@ LoadInfo::LoadInfo(const LoadInfo& rhs)
       mInterceptionInfo(rhs.mInterceptionInfo),
       mHasInjectedCookieForCookieBannerHandling(
           rhs.mHasInjectedCookieForCookieBannerHandling),
-      mWasSchemelessInput(rhs.mWasSchemelessInput) {
+      mWasSchemelessInput(rhs.mWasSchemelessInput),
+      mIsNewWindowTarget(rhs.mIsNewWindowTarget) {
 }
 
 LoadInfo::LoadInfo(
@@ -738,7 +739,8 @@ LoadInfo::LoadInfo(
     nsILoadInfo::CrossOriginEmbedderPolicy aLoadingEmbedderPolicy,
     bool aIsOriginTrialCoepCredentiallessEnabledForTopLevel,
     nsIURI* aUnstrippedURI, nsIInterceptionInfo* aInterceptionInfo,
-    bool aHasInjectedCookieForCookieBannerHandling, bool aWasSchemelessInput)
+    bool aHasInjectedCookieForCookieBannerHandling, bool aWasSchemelessInput,
+    bool aIsNewWindowTarget)
     : mLoadingPrincipal(aLoadingPrincipal),
       mTriggeringPrincipal(aTriggeringPrincipal),
       mPrincipalToInherit(aPrincipalToInherit),
@@ -816,7 +818,8 @@ LoadInfo::LoadInfo(
       mInterceptionInfo(aInterceptionInfo),
       mHasInjectedCookieForCookieBannerHandling(
           aHasInjectedCookieForCookieBannerHandling),
-      mWasSchemelessInput(aWasSchemelessInput) {
+      mWasSchemelessInput(aWasSchemelessInput),
+      mIsNewWindowTarget(aIsNewWindowTarget) {
   // Only top level TYPE_DOCUMENT loads can have a null loadingPrincipal
   MOZ_ASSERT(mLoadingPrincipal ||
              aContentPolicyType == nsIContentPolicy::TYPE_DOCUMENT);
@@ -2416,4 +2419,16 @@ LoadInfo::SetWasSchemelessInput(bool aWasSchemelessInput) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+LoadInfo::GetIsNewWindowTarget(bool* aIsNewWindowTarget) {
+  *aIsNewWindowTarget = mIsNewWindowTarget;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+LoadInfo::SetIsNewWindowTarget(bool aIsNewWindowTarget) {
+  mIsNewWindowTarget = aIsNewWindowTarget;
+  return NS_OK;
+}
+
 }  // namespace mozilla::net
diff --git a/netwerk/base/LoadInfo.h b/netwerk/base/LoadInfo.h
index e6badeeee816..65b8ed84b05a 100644
--- a/netwerk/base/LoadInfo.h
+++ b/netwerk/base/LoadInfo.h
@@ -258,7 +258,9 @@ class LoadInfo final : public nsILoadInfo {
       nsILoadInfo::CrossOriginEmbedderPolicy aLoadingEmbedderPolicy,
       bool aIsOriginTrialCoepCredentiallessEnabledForTopLevel,
       nsIURI* aUnstrippedURI, nsIInterceptionInfo* aInterceptionInfo,
-      bool aHasInjectedCookieForCookieBannerHandling, bool aWasSchemelessInput);
+      bool aHasInjectedCookieForCookieBannerHandling, bool aWasSchemelessInput,
+      bool aIsNewWindowTarget);
+
   LoadInfo(const LoadInfo& rhs);
 
   NS_IMETHOD GetRedirects(JSContext* aCx,
@@ -408,6 +410,8 @@ class LoadInfo final : public nsILoadInfo {
 
   bool mHasInjectedCookieForCookieBannerHandling = false;
   bool mWasSchemelessInput = false;
+
+  bool mIsNewWindowTarget = false;
 };
 
 // This is exposed solely for testing purposes and should not be used outside of
diff --git a/netwerk/base/TRRLoadInfo.cpp b/netwerk/base/TRRLoadInfo.cpp
index 48560a8b3be4..723724a29f35 100644
--- a/netwerk/base/TRRLoadInfo.cpp
+++ b/netwerk/base/TRRLoadInfo.cpp
@@ -870,5 +870,15 @@ TRRLoadInfo::SetWasSchemelessInput(bool aWasSchemelessInput) {
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+NS_IMETHODIMP
+TRRLoadInfo::GetIsNewWindowTarget(bool* aIsNewWindowTarget) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+TRRLoadInfo::SetIsNewWindowTarget(bool aIsNewWindowTarget) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
 }  // namespace net
 }  // namespace mozilla
diff --git a/netwerk/base/nsILoadInfo.idl b/netwerk/base/nsILoadInfo.idl
index 8ff5e556c986..dffc6bddef3d 100644
--- a/netwerk/base/nsILoadInfo.idl
+++ b/netwerk/base/nsILoadInfo.idl
@@ -1544,4 +1544,10 @@ interface nsILoadInfo : nsISupports
    * Whether the load has gone through the URL bar, where the fixup had to add * the protocol scheme.
    */
    [infallible] attribute boolean wasSchemelessInput;
+
+  /**
+   * Is this the first load in a new pop-up window/tab?
+   */
+  [infallible] attribute boolean isNewWindowTarget;
+
 };
diff --git a/netwerk/ipc/DocumentLoadListener.cpp b/netwerk/ipc/DocumentLoadListener.cpp
index dfd80e8867ec..ab97bbfd77f5 100644
--- a/netwerk/ipc/DocumentLoadListener.cpp
+++ b/netwerk/ipc/DocumentLoadListener.cpp
@@ -1646,13 +1646,8 @@ void DocumentLoadListener::SerializeRedirectData(
 }
 
 static bool IsFirstLoadInWindow(nsIChannel* aChannel) {
-  if (nsCOMPtr<nsIPropertyBag2> props = do_QueryInterface(aChannel)) {
-    bool tmp = false;
-    nsresult rv =
-        props->GetPropertyAsBool(u"docshell.newWindowTarget"_ns, &tmp);
-    return NS_SUCCEEDED(rv) && tmp;
-  }
-  return false;
+  nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo();
+  return loadInfo->GetIsNewWindowTarget();
 }
 
 // Get where the document loaded by this nsIChannel should be rendered. This
diff --git a/netwerk/ipc/NeckoChannelParams.ipdlh b/netwerk/ipc/NeckoChannelParams.ipdlh
index 2b3fddd54c9a..c3b428a0328d 100644
--- a/netwerk/ipc/NeckoChannelParams.ipdlh
+++ b/netwerk/ipc/NeckoChannelParams.ipdlh
@@ -192,6 +192,7 @@ struct LoadInfoArgs
   bool                        originTrialCoepCredentiallessEnabledForTopLevel;
   nullable nsIURI             unstrippedURI;
   InterceptionInfoArg?        interceptionInfo;
+  bool                        isNewWindowTarget;
 };
 
 /**
diff --git a/uriloader/exthandler/ExternalHelperAppParent.cpp b/uriloader/exthandler/ExternalHelperAppParent.cpp
index 96c7444abac7..9b43e4870cc3 100644
--- a/uriloader/exthandler/ExternalHelperAppParent.cpp
+++ b/uriloader/exthandler/ExternalHelperAppParent.cpp
@@ -62,8 +62,7 @@ ExternalHelperAppParent::ExternalHelperAppParent(
 bool ExternalHelperAppParent::Init(
     const mozilla::net::LoadInfoArgs& aLoadInfoArgs,
     const nsACString& aMimeContentType, const bool& aForceSave,
-    nsIURI* aReferrer, BrowsingContext* aContext,
-    const bool& aShouldCloseWindow) {
+    nsIURI* aReferrer, BrowsingContext* aContext) {
   nsresult rv = mozilla::ipc::LoadInfoArgsToLoadInfo(
       aLoadInfoArgs, ContentParent::Cast(Manager())->GetRemoteType(),
       getter_AddRefs(mLoadInfo));
@@ -95,18 +94,7 @@ bool ExternalHelperAppParent::Init(
 
   helperAppService->CreateListener(aMimeContentType, this, aContext, aForceSave,
                                    nullptr, getter_AddRefs(mListener));
-  if (!mListener) {
-    return false;
-  }
-
-  if (aShouldCloseWindow) {
-    RefPtr<nsExternalAppHandler> handler = do_QueryObject(mListener);
-    if (handler) {
-      handler->SetShouldCloseWindow();
-    }
-  }
-
-  return true;
+  return mListener != nullptr;
 }
 
 void ExternalHelperAppParent::ActorDestroy(ActorDestroyReason why) {
diff --git a/uriloader/exthandler/ExternalHelperAppParent.h b/uriloader/exthandler/ExternalHelperAppParent.h
index 540889e648e6..2f9096c2383a 100644
--- a/uriloader/exthandler/ExternalHelperAppParent.h
+++ b/uriloader/exthandler/ExternalHelperAppParent.h
@@ -87,8 +87,7 @@ class ExternalHelperAppParent
                           const nsAString& aContentDispositionFilename);
   bool Init(const mozilla::net::LoadInfoArgs& aLoadInfoArgs,
             const nsACString& aMimeContentType, const bool& aForceSave,
-            nsIURI* aReferrer, BrowsingContext* aContext,
-            const bool& aShouldCloseWindow);
+            nsIURI* aReferrer, BrowsingContext* aContext);
 
  protected:
   virtual ~ExternalHelperAppParent();
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index 364cfae0f849..559a8b3366cc 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -678,14 +678,6 @@ nsresult nsExternalHelperAppService::DoContentContentProcessHelper(
   mozilla::net::LoadInfoArgs loadInfoArgs;
   MOZ_ALWAYS_SUCCEEDS(LoadInfoToLoadInfoArgs(loadInfo, &loadInfoArgs));
 
-  nsCOMPtr<nsIPropertyBag2> props(do_QueryInterface(aChannel));
-  // Determine whether a new window was opened specifically for this request
-  bool shouldCloseWindow = false;
-  if (props) {
-    props->GetPropertyAsBool(u"docshell.newWindowTarget"_ns,
-                             &shouldCloseWindow);
-  }
-
   // Now we build a protocol for forwarding our data to the parent.  The
   // protocol will act as a listener on the child-side and create a "real"
   // helperAppService listener on the parent-side, via another call to
@@ -694,7 +686,7 @@ nsresult nsExternalHelperAppService::DoContentContentProcessHelper(
   MOZ_ALWAYS_TRUE(child->SendPExternalHelperAppConstructor(
       childListener, uri, loadInfoArgs, nsCString(aMimeContentType), disp,
       contentDisposition, fileName, aForceSave, contentLength, wasFileChannel,
-      referrer, aContentContext, shouldCloseWindow));
+      referrer, aContentContext));
 
   NS_ADDREF(*aStreamListener = childListener);
 
@@ -1287,7 +1279,6 @@ nsExternalAppHandler::nsExternalAppHandler(
       mCanceled(false),
       mStopRequestIssued(false),
       mIsFileChannel(false),
-      mShouldCloseWindow(false),
       mHandleInternally(false),
       mDialogShowing(false),
       mReason(aReason),
@@ -1603,15 +1594,12 @@ NS_IMETHODIMP nsExternalAppHandler::OnStartRequest(nsIRequest* request) {
 
   if (mBrowsingContext) {
     mMaybeCloseWindowHelper = new MaybeCloseWindowHelper(mBrowsingContext);
-    mMaybeCloseWindowHelper->SetShouldCloseWindow(mShouldCloseWindow);
-    nsCOMPtr<nsIPropertyBag2> props(do_QueryInterface(request, &rv));
+
     // Determine whether a new window was opened specifically for this request
-    if (props) {
-      bool tmp = false;
-      if (NS_SUCCEEDED(
-              props->GetPropertyAsBool(u"docshell.newWindowTarget"_ns, &tmp))) {
-        mMaybeCloseWindowHelper->SetShouldCloseWindow(tmp);
-      }
+    if (aChannel) {
+      nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo();
+      mMaybeCloseWindowHelper->SetShouldCloseWindow(
+          loadInfo->GetIsNewWindowTarget());
     }
   }
 
diff --git a/uriloader/exthandler/nsExternalHelperAppService.h b/uriloader/exthandler/nsExternalHelperAppService.h
index e880b90b2df8..2dd4ff87bda3 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.h
+++ b/uriloader/exthandler/nsExternalHelperAppService.h
@@ -315,8 +315,6 @@ class nsExternalAppHandler final : public nsIStreamListener,
    */
   void MaybeApplyDecodingForExtension(nsIRequest* request);
 
-  void SetShouldCloseWindow() { mShouldCloseWindow = true; }
-
  protected:
   bool IsDownloadSpam(nsIChannel* aChannel);
 
@@ -382,12 +380,6 @@ class nsExternalAppHandler final : public nsIStreamListener,
 
   bool mIsFileChannel;
 
-  /**
-   * True if the ExternalHelperAppChild told us that we should close the window
-   * if we handle the content as a download.
-   */
-  bool mShouldCloseWindow;
-
   /**
    * True if the file should be handled internally.
    */
diff --git a/uriloader/exthandler/nsExternalProtocolHandler.cpp b/uriloader/exthandler/nsExternalProtocolHandler.cpp
index 37eccac85f92..815f40cd24aa 100644
--- a/uriloader/exthandler/nsExternalProtocolHandler.cpp
+++ b/uriloader/exthandler/nsExternalProtocolHandler.cpp
@@ -21,7 +21,6 @@
 #include "nsNetUtil.h"
 #include "nsContentSecurityManager.h"
 #include "nsExternalHelperAppService.h"
-#include "nsHashPropertyBag.h"
 
 // used to dispatch urls to default protocol handlers
 #include "nsCExternalHandlerService.h"
@@ -36,12 +35,11 @@ class nsILoadInfo;
 // OpenInputStream to calls in the OS for loading the url.
 ////////////////////////////////////////////////////////////////////////
 
-class nsExtProtocolChannel : public nsHashPropertyBag,
-                             public nsIChannel,
+class nsExtProtocolChannel : public nsIChannel,
                              public nsIChildChannel,
                              public nsIParentChannel {
  public:
-  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSICHANNEL
   NS_DECL_NSIREQUESTOBSERVER
   NS_DECL_NSISTREAMLISTENER
@@ -75,17 +73,18 @@ class nsExtProtocolChannel : public nsHashPropertyBag,
   nsCOMPtr<nsIStreamListener> mListener;
 };
 
-NS_IMPL_ADDREF_INHERITED(nsExtProtocolChannel, nsHashPropertyBag)
-NS_IMPL_RELEASE_INHERITED(nsExtProtocolChannel, nsHashPropertyBag)
+NS_IMPL_ADDREF(nsExtProtocolChannel)
+NS_IMPL_RELEASE(nsExtProtocolChannel)
 
 NS_INTERFACE_MAP_BEGIN(nsExtProtocolChannel)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIChannel)
   NS_INTERFACE_MAP_ENTRY(nsIChannel)
   NS_INTERFACE_MAP_ENTRY(nsIRequest)
   NS_INTERFACE_MAP_ENTRY(nsIChildChannel)
   NS_INTERFACE_MAP_ENTRY(nsIParentChannel)
   NS_INTERFACE_MAP_ENTRY(nsIStreamListener)
   NS_INTERFACE_MAP_ENTRY(nsIRequestObserver)
-NS_INTERFACE_MAP_END_INHERITING(nsHashPropertyBag)
+NS_INTERFACE_MAP_END
 
 nsExtProtocolChannel::nsExtProtocolChannel(nsIURI* aURI, nsILoadInfo* aLoadInfo)
     : mUrl(aURI),
@@ -177,13 +176,10 @@ nsresult nsExtProtocolChannel::OpenURL() {
       mLoadInfo->RedirectChain().LastElement()->GetPrincipal(
           getter_AddRefs(redirectPrincipal));
     }
-    bool newWindowTarget = false;
-    GetPropertyAsBool(u"docshell.newWindowTarget"_ns, &newWindowTarget);
-
     rv = extProtService->LoadURI(mUrl, triggeringPrincipal, redirectPrincipal,
                                  ctx, mLoadInfo->GetLoadTriggeredFromExternal(),
                                  mLoadInfo->GetHasValidUserGestureActivation(),
-                                 newWindowTarget);
+                                 mLoadInfo->GetIsNewWindowTarget());
 
     if (NS_SUCCEEDED(rv) && mListener) {
       mStatus = NS_ERROR_NO_CONTENT;
diff --git a/uriloader/exthandler/tests/mochitest/browser_protocol_ask_dialog.js b/uriloader/exthandler/tests/mochitest/browser_protocol_ask_dialog.js
index 8d77898b29fa..c9fa16f51301 100644
--- a/uriloader/exthandler/tests/mochitest/browser_protocol_ask_dialog.js
+++ b/uriloader/exthandler/tests/mochitest/browser_protocol_ask_dialog.js
@@ -528,3 +528,68 @@ add_task(async function iframe_popup_tab() {
   gBrowser.removeTab(tab);
   gBrowser.removeTab(newTab);
 });
+
+/**
+ * Check that when navigating to a http channel which redirects to a external
+ * protocol in a noopener pop-up window, we show the dialog in the correct tab.
+ */
+add_task(async function redirect_popup_tab() {
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "https://example.com/"
+  );
+
+  // Wait for the chooser dialog to open in the background tab. It should not
+  // open in the foreground tab which is unrelated to the external protocol
+  // navigation.
+  let dialogWindowPromise = waitForProtocolAppChooserDialog(gBrowser, true);
+
+  // Wait for the new tab to appear. The URI in this tab will never change from
+  // `about:blank` as we're going to just end up opening a dialog, so we can't
+  // use `waitForNewTab`, as that will wait for the tab to actually load
+  // something.
+  let newTabPromise = new Promise(resolve => {
+    gBrowser.tabContainer.addEventListener(
+      "TabOpen",
+      openEvent => resolve(openEvent.target),
+      { once: true }
+    );
+  });
+
+  info("Navigating to redirect to external proto in pop-up");
+  await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [TEST_PATH + "redirect_helper.sjs?uri=mailto:example@example.com"],
+    async function (popupUri) {
+      content.eval("window.open('" + popupUri + "', '_blank', 'noopener');");
+    }
+  );
+
+  // Wait for the new tab to be opened.
+  info("Waiting for new tab to appear");
+  let newTab = await newTabPromise;
+
+  // Wait for dialog to open in one of the tabs.
+  info("Waiting for dialog to appear");
+  let dialog = await dialogWindowPromise;
+
+  is(
+    gBrowser.getTabDialogBox(newTab.linkedBrowser)._tabDialogManager._topDialog,
+    dialog,
+    "Dialog opened in the background tab"
+  );
+
+  is(
+    dialog._frame.contentDocument.location.href,
+    CONTENT_HANDLING_URL,
+    "Opened dialog is appChooser dialog."
+  );
+
+  // Close the dialog:
+  let dialogClosedPromise = waitForProtocolAppChooserDialog(gBrowser, false);
+  dialog.close();
+  await dialogClosedPromise;
+
+  gBrowser.removeTab(tab);
+  gBrowser.removeTab(newTab);
+});