From 1f7ac15b8de6d6321c6ee84b0178ef6dc8aa22da Mon Sep 17 00:00:00 2001
From: Soren Stoutner <soren@stoutner.com>
Date: Wed, 29 Jan 2025 15:48:43 -0700
Subject: [PATCH] Fix loading of websites when the user agent changes. 
 https://redmine.stoutner.com/issues/821

---
 COPYING                                       |  10 +-
 doc/index.docbook                             |  25 ++---
 src/CMakeLists.txt                            |   6 +-
 ... com.stoutner.privacybrowser.metainfo.xml} |   0
 src/dialogs/DomainSettingsDialog.cpp          |  15 ++-
 src/icons/javascript-warning.svg              |   2 +-
 src/icons/privacy-mode.svg                    |   2 +-
 src/icons/privacybrowser-symbolic.svg         |   2 +-
 src/icons/sc-apps-privacybrowser.svg          |   2 +-
 src/interceptors/UrlRequestInterceptor.cpp    |  40 +++++--
 src/interceptors/UrlRequestInterceptor.h      |   4 +-
 src/main.cpp                                  |   4 +-
 src/widgets/PrivacyWebEngineView.cpp          | 105 ++++++++++++++----
 src/widgets/PrivacyWebEngineView.h            |   8 +-
 src/widgets/TabWidget.cpp                     |   6 +-
 15 files changed, 160 insertions(+), 71 deletions(-)
 rename src/{com.stoutner.privacybrowser.appdata.xml => com.stoutner.privacybrowser.metainfo.xml} (100%)

diff --git a/COPYING b/COPYING
index bc16d08..ab6ac2b 100644
--- a/COPYING
+++ b/COPYING
@@ -1,5 +1,5 @@
 SPDX-License-Identifier: GPL-3.0-or-later
-SPDX-FileCopyrightText: 2016-2017, 2021-2024 Soren Stoutner <soren@stoutner.com>
+SPDX-FileCopyrightText: 2016-2017, 2021-2025 Soren Stoutner <soren@stoutner.com>
 
 This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
 
@@ -17,7 +17,7 @@ details.
                     GNU GENERAL PUBLIC LICENSE
                        Version 3, 29 June 2007
 
- Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
@@ -661,7 +661,7 @@ the "copyright" line and a pointer to where the full notice is found.
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 Also add information on how to contact you by electronic and paper mail.
 
@@ -680,11 +680,11 @@ might be different; for a GUI interface, you would use an "about box".
   You should also get your employer (if you work as a programmer) or school,
 if any, to sign a "copyright disclaimer" for the program, if necessary.
 For more information on this, and how to apply and follow the GNU GPL, see
-<http://www.gnu.org/licenses/>.
+<https://www.gnu.org/licenses/>.
 
   The GNU General Public License does not permit incorporating your program
 into proprietary programs.  If your program is a subroutine library, you
 may consider it more useful to permit linking proprietary applications with
 the library.  If this is what you want to do, use the GNU Lesser General
 Public License instead of this License.  But first, please read
-<http://www.gnu.org/philosophy/why-not-lgpl.html>.
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/doc/index.docbook b/doc/index.docbook
index 3bd7754..f685525 100644
--- a/doc/index.docbook
+++ b/doc/index.docbook
@@ -1,23 +1,18 @@
 <?xml version="1.0" ?>
 
 <!--
-  SPDX-License-Identifier: GPL-3.0-or-later
-  SPDX-FileCopyrightText: 2023-2024 Soren Stoutner <soren@stoutner.com>
+  SPDX-License-Identifier: GFDL-1.3-no-invariants-or-later
+  SPDX-FileCopyrightText: 2023-2025 Soren Stoutner <soren@stoutner.com>
 
   This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
 
-  This program is free software: you can redistribute it and/or modify it under
-  the terms of the GNU General Public License as published by the Free Software
-  Foundation, either version 3 of the License, or (at your option) any later
-  version.
+  Permission is granted to copy, distribute and/or modify this document
+  under the terms of the GNU Free Documentation License, Version 1.3
+  or any later version published by the Free Software Foundation;
+  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 
-  This program is distributed in the hope that it will be useful, but WITHOUT
-  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
-  details.
-
-  You should have received a copy of the GNU General Public License along with
-  this program.  If not, see <https://www.gnu.org/licenses/>. -->
+  You should have received a copy of the GNU Free Documentation License
+  along with this program.  If not, see <https://www.gnu.org/licenses/>. -->
 
 <!DOCTYPE book PUBLIC "-//KDE//DTD DocBook XML V4.5-Based Variant V1.1//EN" "dtd/kdedbx45.dtd" [
     <!-- Privacy Browser’s name -->
@@ -42,7 +37,7 @@
         </authorgroup>
 
         <copyright>
-            <year>2016-2017, 2021-2024</year>
+            <year>2016-2017, 2021-2025</year>
             <holder>&Soren.Stoutner;</holder>
         </copyright>
 
@@ -2018,7 +2013,7 @@
         <title>Credits and License</title>
 
         <para>
-            Privacy Browser PC copyright 2016-2017, 2021-2024 Soren Stoutner <ulink url="mailto:soren@stoutner.com">soren@stoutner.com</ulink>.
+            Privacy Browser PC copyright 2016-2017, 2021-2025 Soren Stoutner <ulink url="mailto:soren@stoutner.com">soren@stoutner.com</ulink>.
         </para>
 
         <!-- Program. -->
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a5e0a2f..799c44e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
-# SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+# SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
 #
 # This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
 #
@@ -97,8 +97,8 @@ install(TARGETS privacybrowser ${KDE_INSTALL_TARGETS_DEFAULT_ARGS})
 # Install Privacy Browser according to the instructions in the desktop file, specifying the permissions.
 install(PROGRAMS com.stoutner.privacybrowser.desktop DESTINATION ${KDE_INSTALL_APPDIR} PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ)
 
-# Install the metadata file.
-install(FILES com.stoutner.privacybrowser.appdata.xml DESTINATION ${KDE_INSTALL_METAINFODIR})
+# Install the metainfo file.
+install(FILES com.stoutner.privacybrowser.metainfo.xml DESTINATION ${KDE_INSTALL_METAINFODIR})
 
 # Install the notifyrc file.
 install(FILES privacybrowser.notifyrc DESTINATION ${KDE_INSTALL_KNOTIFYRCDIR})
diff --git a/src/com.stoutner.privacybrowser.appdata.xml b/src/com.stoutner.privacybrowser.metainfo.xml
similarity index 100%
rename from src/com.stoutner.privacybrowser.appdata.xml
rename to src/com.stoutner.privacybrowser.metainfo.xml
diff --git a/src/dialogs/DomainSettingsDialog.cpp b/src/dialogs/DomainSettingsDialog.cpp
index 8c77d6d..96ea20f 100644
--- a/src/dialogs/DomainSettingsDialog.cpp
+++ b/src/dialogs/DomainSettingsDialog.cpp
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+ * SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
  *
  * This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
  *
@@ -300,6 +300,19 @@ void DomainSettingsDialog::domainSelected(const QModelIndex &modelIndex) const
     // Populate the zoom factor combo box.
     zoomFactorComboBoxPointer->setCurrentIndex(zoomFactorComboBoxIndex);
 
+    // Get the combo box palette.
+    QPalette comboBoxPalette = zoomFactorComboBoxPointer->palette();
+
+    // Get the combo box window color.
+    QColor comboBoxWindowColor = comboBoxPalette.color(QPalette::Window);
+
+    // Set the combo box window color back to the palette.  This makes the system think the palette has changed.
+    comboBoxPalette.setColor(QPalette::Window, comboBoxWindowColor);
+
+    // Explicitly set the combo box palette.  Because the system thinks the palette has been changed, and because the combo box palette is being explicitly set,
+    // the system will not propagate the highlighted palette from the widget pointer palette down to the combo box.  <https://redmine.stoutner.com/issues/1252>
+    zoomFactorComboBoxPointer->setPalette(comboBoxPalette);
+
     // Populate the custom zoom factor spin box according to the zoom factor combo box.
     if (zoomFactorComboBoxIndex == 0)  // System default zoom factor is selected.
     {
diff --git a/src/icons/javascript-warning.svg b/src/icons/javascript-warning.svg
index c9e4542..4da7a56 100644
--- a/src/icons/javascript-warning.svg
+++ b/src/icons/javascript-warning.svg
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 
 <!--
-  Copyright © 2016-2017,2021-2022 Soren Stoutner <soren@stoutner.com>.
+  Copyright 2016-2017, 2021-2022 Soren Stoutner <soren@stoutner.com>.
 
   This file is derived from `security` and `language`, which are part of the Android Material icon set.  They are released under the Apache License 2.0.  <https://fonts.google.com/icons>
 
diff --git a/src/icons/privacy-mode.svg b/src/icons/privacy-mode.svg
index d799bd8..7eb3a06 100644
--- a/src/icons/privacy-mode.svg
+++ b/src/icons/privacy-mode.svg
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 
 <!--
-  Copyright © 2016-2017,2021-2022 Soren Stoutner <soren@stoutner.com>.
+  Copyright 2016-2017, 2021-2022 Soren Stoutner <soren@stoutner.com>.
 
   This file is derived from `security` and `language`, which are part of the Android Material icon set.  They are released under the Apache License 2.0.  <https://fonts.google.com/icons>
 
diff --git a/src/icons/privacybrowser-symbolic.svg b/src/icons/privacybrowser-symbolic.svg
index 9649f6f..98d68cf 100644
--- a/src/icons/privacybrowser-symbolic.svg
+++ b/src/icons/privacybrowser-symbolic.svg
@@ -10,7 +10,7 @@
 </svg>
 
 <!--
-  Copyright 2016-2017,2021-2023 Soren Stoutner <soren@stoutner.com>.
+  Copyright 2016-2017, 2021-2023 Soren Stoutner <soren@stoutner.com>.
 
   This file is derived from `security` and `language`, which are part of the Android Material icon set.  They are released under the Apache License 2.0.  <https://fonts.google.com/icons>
 
diff --git a/src/icons/sc-apps-privacybrowser.svg b/src/icons/sc-apps-privacybrowser.svg
index 19bf69f..290ef36 100644
--- a/src/icons/sc-apps-privacybrowser.svg
+++ b/src/icons/sc-apps-privacybrowser.svg
@@ -27,7 +27,7 @@
 </svg>
 
 <!--
-  Copyright 2016-2017,2021-2023 Soren Stoutner <soren@stoutner.com>.
+  Copyright 2016-2017, 2021-2023 Soren Stoutner <soren@stoutner.com>.
 
   This file is derived from `security` and `language`, which are part of the Android Material icon set.  They are released under the Apache License 2.0.  <https://fonts.google.com/icons>
 
diff --git a/src/interceptors/UrlRequestInterceptor.cpp b/src/interceptors/UrlRequestInterceptor.cpp
index ffdacd2..ccaa179 100644
--- a/src/interceptors/UrlRequestInterceptor.cpp
+++ b/src/interceptors/UrlRequestInterceptor.cpp
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+ * SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
  *
  * This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
  *
@@ -85,20 +85,44 @@ void UrlRequestInterceptor::interceptRequest(QWebEngineUrlRequestInfo &urlReques
     {
         case QWebEngineUrlRequestInfo::NavigationTypeLink:
         case QWebEngineUrlRequestInfo::NavigationTypeTyped:
-        case QWebEngineUrlRequestInfo::NavigationTypeBackForward:
-        // case QWebEngineUrlRequestInfo::NavigationTypeReload:  This can be uncommented once https://redmine.stoutner.com/issues/821 has been fixed.
+        case QWebEngineUrlRequestInfo::NavigationTypeFormSubmitted:
         case QWebEngineUrlRequestInfo::NavigationTypeRedirect:
+        case QWebEngineUrlRequestInfo::NavigationTypeOther:
+        {
+            // Only check the hosts if the main URL is changing.
+            if (urlRequestInfo.resourceType() == QWebEngineUrlRequestInfo::ResourceTypeMainFrame)
+            {
+                // Get the request URL.
+                QUrl requestUrl = urlRequestInfo.requestUrl();
+
+                // Reapply the domain settings if the host is changing.
+                if (privacyWebEngineViewPointer->currentHost != requestUrl.host())
+                {
+                    // Apply domain settings, after which the request will be loaded.  `false` indicates that history is not being navigated.
+                    Q_EMIT applyDomainSettings(requestUrl, false);
+
+                    // Block this copy of the request.
+                    urlRequestInfo.block(true);
+                }
+            }
+
+            break;
+        }
+
+        case QWebEngineUrlRequestInfo::NavigationTypeBackForward:
         {
             // Only check the hosts if the main URL is changing.
             if (urlRequestInfo.resourceType() == QWebEngineUrlRequestInfo::ResourceTypeMainFrame)
             {
-                // Get the hosts.
-                QString requestingHost = urlRequestInfo.initiator().host();
-                QString requestedHost = urlRequestInfo.requestUrl().host();
+                // Get the request URL.
+                QUrl requestUrl = urlRequestInfo.requestUrl();
 
                 // Reapply the domain settings if the host is changing.
-                if (requestingHost != requestedHost)
-                    Q_EMIT applyDomainSettings(requestedHost);
+                if (privacyWebEngineViewPointer->currentHost != requestUrl.host())
+                {
+                    // Apply domain settings, after which the request will be loaded.  `true` indicates that history is being navigated.
+                    Q_EMIT applyDomainSettings(requestUrl, true);
+                }
             }
 
             break;
diff --git a/src/interceptors/UrlRequestInterceptor.h b/src/interceptors/UrlRequestInterceptor.h
index 0fffa2b..4a3d635 100644
--- a/src/interceptors/UrlRequestInterceptor.h
+++ b/src/interceptors/UrlRequestInterceptor.h
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+ * SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
  *
  * This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
  *
@@ -41,7 +41,7 @@ public:
 
 Q_SIGNALS:
     // The signals.
-    void applyDomainSettings(const QString &hostname) const;
+    void applyDomainSettings(const QUrl &url, const bool navigatingHistory) const;
     void displayHttpPingDialog(const QString &httpPingUrl) const;
     void newMainFrameResource() const;
     void requestProcessed(RequestStruct *requestStruct) const;
diff --git a/src/main.cpp b/src/main.cpp
index 8b56619..fafa0dc 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+ * SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
  *
  * This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
  *
@@ -61,7 +61,7 @@ int main(int argc, char *argv[])
 
     // Populate additional about data info.
     aboutData.setBugAddress("https://redmine.stoutner.com/projects/privacy-browser-pc/issues");
-    aboutData.setCopyrightStatement(i18nc("Copyright", "Copyright 2016-2017, 2021-2024 Soren Stoutner <soren@stoutner.com>"));
+    aboutData.setCopyrightStatement(i18nc("Copyright", "Copyright 2016-2017, 2021-2025 Soren Stoutner <soren@stoutner.com>"));
     aboutData.setDesktopFileName(QLatin1String("com.stoutner.privacybrowser"));
     aboutData.setHomepage(QLatin1String("https://www.stoutner.com/privacy-browser-pc/"));
     //aboutData.setLicense(KAboutLicense::GPL_V3, KAboutLicense::OrLaterVersions);  <https://redmine.stoutner.com/issues/822>
diff --git a/src/widgets/PrivacyWebEngineView.cpp b/src/widgets/PrivacyWebEngineView.cpp
index 945c007..27cb2ab 100644
--- a/src/widgets/PrivacyWebEngineView.cpp
+++ b/src/widgets/PrivacyWebEngineView.cpp
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+ * SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
  *
  * This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
  *
@@ -56,7 +56,7 @@ PrivacyWebEngineView::PrivacyWebEngineView(QWidget *parentWidgetPointer) : QWebE
     webEngineProfilePointer->setUrlRequestInterceptor(urlRequestInterceptorPointer);
 
     // Connect the URL request interceptor signals.
-    connect(urlRequestInterceptorPointer, SIGNAL(applyDomainSettings(const QString&)), this, SLOT(applyDomainSettingsWithoutReloading(const QString&)));
+    connect(urlRequestInterceptorPointer, SIGNAL(applyDomainSettings(const QUrl&, const bool)), this, SLOT(applyDomainSettings(const QUrl&, const bool)));
     connect(urlRequestInterceptorPointer, SIGNAL(newMainFrameResource()), this, SLOT(clearRequestsList()));
     connect(urlRequestInterceptorPointer, SIGNAL(displayHttpPingDialog(const QString&)), this, SLOT(displayHttpPingDialog(const QString&)));
     connect(urlRequestInterceptorPointer, SIGNAL(requestProcessed(RequestStruct*)), this, SLOT(storeRequest(RequestStruct*)));
@@ -86,19 +86,19 @@ void PrivacyWebEngineView::addCookieToList(const QNetworkCookie &cookie) const
     Q_EMIT numberOfCookiesChanged(cookieListPointer->size());
 }
 
-void PrivacyWebEngineView::applyDomainSettingsWithoutReloading(const QString &hostname)
+void PrivacyWebEngineView::applyDomainSettings(const QUrl &newUrl, const bool navigatingHistory)
 {
-    // Apply the domain settings  `false` does not reload the website.
-    applyDomainSettings(hostname, false);
-}
+    // Store the current host.
+    currentHost = newUrl.host();
 
-void PrivacyWebEngineView::applyDomainSettings(const QString &hostname, const bool reloadWebsite)
-{
-    // Get the record for the hostname.
-    QSqlQuery domainQuery = DomainsDatabase::getDomainQuery(hostname);
+    // Create a user agent changed tracker.
+    bool userAgentChanged = false;
 
-    // Check if the hostname has domain settings.
-    if (domainQuery.isValid())  // The hostname has domain settings.
+    // Get the record for the current host.
+    QSqlQuery domainQuery = DomainsDatabase::getDomainQuery(currentHost);
+
+    // Check if the current host has domain settings.
+    if (domainQuery.isValid())  // The current host has domain settings.
     {
         // Store the domain settings name.
         domainSettingsName = domainQuery.value(DomainsDatabase::DOMAIN_NAME).toString();
@@ -127,8 +127,15 @@ void PrivacyWebEngineView::applyDomainSettings(const QString &hostname, const bo
             case (DomainsDatabase::DISABLED): webEngineSettingsPointer->setAttribute(QWebEngineSettings::LocalStorageEnabled, false); break;
         }
 
-        // Set the user agent.
-        webEngineProfilePointer->setHttpUserAgent(UserAgentHelper::getResultingDomainSettingsUserAgent(domainQuery.value(DomainsDatabase::USER_AGENT).toString()));
+        // Get the domain settings user agent.
+        QString domainSettingsUserAgent = UserAgentHelper::getResultingDomainSettingsUserAgent(domainQuery.value(DomainsDatabase::USER_AGENT).toString());
+
+        // Determine if the user agent is changing.
+        if (webEngineProfilePointer->httpUserAgent() != domainSettingsUserAgent)
+            userAgentChanged = true;
+
+        // Set the user agent.  Setting the user agent, even if it isn't changing, causes the pre-rendered page to enter a locked state where reload doesn't work.
+        webEngineProfilePointer->setHttpUserAgent(domainSettingsUserAgent);
 
         // Set the UltraPrivacy status.
         switch (domainQuery.value(DomainsDatabase::ULTRAPRIVACY).toInt())
@@ -182,7 +189,7 @@ void PrivacyWebEngineView::applyDomainSettings(const QString &hostname, const bo
             defaultZoomFactor = Settings::zoomFactor();
         }
     }
-    else  // The hostname does not have domain settings.
+    else  // The current host does not have domain settings.
     {
         // Reset the domain settings name.
         domainSettingsName = QLatin1String("");
@@ -196,8 +203,15 @@ void PrivacyWebEngineView::applyDomainSettings(const QString &hostname, const bo
         // Set DOM storage.  In QWebEngineSettings it is called Local Storage.
         webEngineSettingsPointer->setAttribute(QWebEngineSettings::LocalStorageEnabled, Settings::domStorageEnabled());
 
-        // Set the user agent.
-        webEngineProfilePointer->setHttpUserAgent(UserAgentHelper::getUserAgentFromDatabaseName(Settings::userAgent()));
+        // Get the default user agent.
+        QString defaultUserAgent = UserAgentHelper::getUserAgentFromDatabaseName(Settings::userAgent());
+
+        // Determine if the user agent is changing.
+        if (webEngineProfilePointer->httpUserAgent() != defaultUserAgent)
+            userAgentChanged = true;
+
+        // Set the user agent.  Setting the user agent, even if it isn't changing, causes the pre-rendered page to enter a locked state where reload doesn't work.
+        webEngineProfilePointer->setHttpUserAgent(defaultUserAgent);
 
         // Set the status for each filter list.
         ultraPrivacyEnabled = Settings::ultraPrivacyEnabled();
@@ -213,15 +227,57 @@ void PrivacyWebEngineView::applyDomainSettings(const QString &hostname, const bo
     // Set the current zoom factor.
     setZoomFactor(defaultZoomFactor);
 
-    // Reload the website if requested.
-    if (reloadWebsite)
-        reload();
-
     // Reset the HTTP authentication dialog counter.
     httpAuthenticationDialogsDisplayed = 0;
 
     // Update the UI.
     Q_EMIT updateUi(this);
+
+    // Reload the URL.
+    // This works around a bug in Qt WebEngine that causes massive problems when the user agent is changed after the page has started pre-rendering.  <https://redmine.stoutner.com/issues/821>
+    if (navigatingHistory)
+    {
+        // Get a handle for the WebEngine history.
+        QWebEngineHistory *webEngineHistoryPointer = history();
+
+        // Navigate the history according to the status of the user agent.
+        if (userAgentChanged)  // The user agent changed.
+        {
+            // Go back once.  This current navigation will fail, but the next one will succeed.
+            //back();
+
+            if (webEngineHistoryPointer->canGoBack() && (newUrl == webEngineHistoryPointer->backItem().url()))
+            {
+                // Go back twice.  The first one will fail, but the second will succeed.
+                back();
+            }
+            else
+            {
+                // Go forward twice.  The first one will fail, but the second will succeed.
+                forward();
+            }
+        }
+        else  // The user agent did not change.
+        {
+            // The WebEngine history will think it has loaded the final URL, and will be in the correct location, but it will have been interrupted and reloaded the original URL.
+            // The solution is to direct the WebEngine history to offset one and then return, which will actually load the correct URL because `applyDomainSettings` will not be triggered.
+            if (webEngineHistoryPointer->canGoForward())
+            {
+                // Go forward and back one.
+                forward();
+                back();
+            }
+            else
+            {
+                // Go back and forward one.
+                back();
+                forward();
+            }
+        }
+    } else {
+        // Load the new URL again.
+        load(newUrl);
+    }
 }
 
 void PrivacyWebEngineView::clearRequestsList()
@@ -241,7 +297,8 @@ void PrivacyWebEngineView::clearRequestsList()
     Q_EMIT requestBlocked(blockedRequestsVector);
 }
 
-void PrivacyWebEngineView::contextMenuEvent(QContextMenuEvent *contextMenuEvent) {
+void PrivacyWebEngineView::contextMenuEvent(QContextMenuEvent *contextMenuEvent)
+{
     // Get a handle for the WebEngine page.
     QWebEnginePage *webEnginePagePointer = page();
 
@@ -304,7 +361,8 @@ void PrivacyWebEngineView::contextMenuEvent(QContextMenuEvent *contextMenuEvent)
     contextMenu->popup(contextMenuEvent->globalPos());
 }
 
-QWebEngineView* PrivacyWebEngineView::createWindow(QWebEnginePage::WebWindowType webWindowType) {
+QWebEngineView* PrivacyWebEngineView::createWindow(QWebEnginePage::WebWindowType webWindowType)
+{
     // Get a handle for the browser window.
     BrowserWindow *browserWindowPointer = qobject_cast<BrowserWindow*>(window());
 
@@ -429,3 +487,4 @@ void PrivacyWebEngineView::storeUpdatedUrl(const QUrl &newUrl)
     // Store the new URL string (which changes when a new page is loaded as the current URL text.  This is important when loading a new tab from a link.  <https://redmine.stoutner.com/issues/1228>
     currentUrlText = newUrl.toString();
 }
+
diff --git a/src/widgets/PrivacyWebEngineView.h b/src/widgets/PrivacyWebEngineView.h
index 5c7e9ae..bf0323e 100644
--- a/src/widgets/PrivacyWebEngineView.h
+++ b/src/widgets/PrivacyWebEngineView.h
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+ * SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
  *
  * This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
  *
@@ -53,6 +53,7 @@ public:
     // The public variables.
     QVector<int> blockedRequestsVector = {0, 0, 0, 0, 0, 0};
     std::list<QNetworkCookie> *cookieListPointer = new std::list<QNetworkCookie>;
+    QString currentHost = QLatin1String("");
     QString currentUrlText = QLatin1String("");
     double defaultZoomFactor = 1.00;
     QString domainSettingsName = QLatin1String("");
@@ -71,9 +72,6 @@ public:
     bool ultraListEnabled = true;
     bool ultraPrivacyEnabled = true;
 
-    // The public functions.
-    void applyDomainSettings(const QString &hostname, const bool reloadWebsite);
-
 Q_SIGNALS:
     // The signals.
     void numberOfCookiesChanged(const int numberOfCookies) const;
@@ -84,11 +82,11 @@ Q_SIGNALS:
 public Q_SLOTS:
     // The public slots.
     void addCookieToList(const QNetworkCookie &cookie) const;
+    void applyDomainSettings(const QUrl &newUrl, const bool navigatingHistory);
     void removeCookieFromList(const QNetworkCookie &cookie) const;
 
 private Q_SLOTS:
     // The private slots.
-    void applyDomainSettingsWithoutReloading(const QString &hostname);
     void clearRequestsList();
     void displayHttpPingDialog(const QString &httpPingUrl) const;
     void handleAuthenticationRequest(const QUrl &requestUrl, QAuthenticator *authenticatorPointer);
diff --git a/src/widgets/TabWidget.cpp b/src/widgets/TabWidget.cpp
index 4213bf2..ba52bf4 100644
--- a/src/widgets/TabWidget.cpp
+++ b/src/widgets/TabWidget.cpp
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2022-2024 Soren Stoutner <soren@stoutner.com>
+ * SPDX-FileCopyrightText: 2022-2025 Soren Stoutner <soren@stoutner.com>
  *
  * This file is part of Privacy Browser PC <https://www.stoutner.com/privacy-browser-pc/>.
  *
@@ -544,8 +544,8 @@ void TabWidget::applyDomainSettingsAndReload()
         // Get the WebEngine view pointer.
         PrivacyWebEngineView *privacyWebEngineViewPointer = qTabWidgetPointer->widget(i)->findChild<PrivacyWebEngineView *>();
 
-        // Apply the domain settings settings to each page.
-        privacyWebEngineViewPointer->applyDomainSettings(privacyWebEngineViewPointer->url().host(), true);
+        // Apply the domain settings settings to each page.  `false` indicates that history is not being navigated.
+        privacyWebEngineViewPointer->applyDomainSettings(privacyWebEngineViewPointer->url(), false);
     }
 }
 
-- 
2.47.2