diff --git a/src/core/framelessconfig.cpp b/src/core/framelessconfig.cpp
index 87cdc81..c98fa33 100644
--- a/src/core/framelessconfig.cpp
+++ b/src/core/framelessconfig.cpp
@@ -93,7 +93,7 @@ FramelessConfig *FramelessConfig::instance()
 
 void FramelessConfig::reload(const bool force)
 {
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     if (g_data()->loaded && !force) {
         return;
     }
@@ -117,25 +117,25 @@ void FramelessConfig::reload(const bool force)
 
 void FramelessConfig::set(const Option option, const bool on)
 {
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     g_data()->options[static_cast<int>(option)] = on;
 }
 
 bool FramelessConfig::isSet(const Option option) const
 {
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     return g_data()->options[static_cast<int>(option)];
 }
 
 void FramelessConfig::setLoadFromEnvironmentVariablesDisabled(const bool on)
 {
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     g_data()->disableEnvVar = on;
 }
 
 void FramelessConfig::setLoadFromConfigurationFileDisabled(const bool on)
 {
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     g_data()->disableCfgFile = on;
 }
 
@@ -147,7 +147,7 @@ std::optional<QVariant> FramelessConfig::setInternal(const QString &key, const Q
         return std::nullopt;
     }
     std::optional<QVariant> previous = std::nullopt;
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     if (g_data()->internals.contains(key)) {
         previous = g_data()->internals.value(key);
         g_data()->internals.remove(key);
@@ -162,7 +162,7 @@ std::optional<QVariant> FramelessConfig::getInternal(const QString &key) const
     if (key.isEmpty()) {
         return std::nullopt;
     }
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     if (g_data()->internals.contains(key)) {
         return g_data()->internals.value(key);
     }
diff --git a/src/core/framelesshelper_qt.cpp b/src/core/framelesshelper_qt.cpp
index 385f1b7..23385dc 100644
--- a/src/core/framelesshelper_qt.cpp
+++ b/src/core/framelesshelper_qt.cpp
@@ -166,7 +166,7 @@ bool FramelessHelperQt::eventFilter(QObject *object, QEvent *event)
     } break;
     case QEvent::MouseButtonRelease: {
         if (button == Qt::LeftButton) {
-            QMutexLocker locker(&g_qtHelper()->mutex);
+            const QMutexLocker locker(&g_qtHelper()->mutex);
             g_qtHelper()->data[windowId].leftButtonPressed = false;
         }
         if (button == Qt::RightButton) {
@@ -191,12 +191,12 @@ bool FramelessHelperQt::eventFilter(QObject *object, QEvent *event)
             if (cs == Qt::ArrowCursor) {
                 if (data.cursorShapeChanged) {
                     window->unsetCursor();
-                    QMutexLocker locker(&g_qtHelper()->mutex);
+                    const QMutexLocker locker(&g_qtHelper()->mutex);
                     g_qtHelper()->data[windowId].cursorShapeChanged = false;
                 }
             } else {
                 window->setCursor(cs);
-                QMutexLocker locker(&g_qtHelper()->mutex);
+                const QMutexLocker locker(&g_qtHelper()->mutex);
                 g_qtHelper()->data[windowId].cursorShapeChanged = true;
             }
         }
diff --git a/src/core/framelesshelper_win.cpp b/src/core/framelesshelper_win.cpp
index 5c839d9..ea9904d 100644
--- a/src/core/framelesshelper_win.cpp
+++ b/src/core/framelesshelper_win.cpp
@@ -257,7 +257,7 @@ Q_GLOBAL_STATIC(Win32Helper, g_win32Helper)
                 WARNING << Utils::getSystemErrorMessage(kTrackMouseEvent);
                 break;
             }
-            QMutexLocker locker(&g_win32Helper()->mutex);
+            const QMutexLocker locker(&g_win32Helper()->mutex);
             g_win32Helper()->data[parentWindowId].trackingMouse = true;
         }
     } break;
@@ -265,7 +265,7 @@ Q_GLOBAL_STATIC(Win32Helper, g_win32Helper)
     case WM_MOUSELEAVE: {
         // When the mouse leaves the drag rect, make sure to dismiss any hover.
         releaseButtons(std::nullopt);
-        QMutexLocker locker(&g_win32Helper()->mutex);
+        const QMutexLocker locker(&g_win32Helper()->mutex);
         g_win32Helper()->data[parentWindowId].trackingMouse = false;
     } break;
     // NB: *Shouldn't be forwarding these* when they're not over the caption
@@ -346,7 +346,7 @@ Q_GLOBAL_STATIC(Win32Helper, g_win32Helper)
     case WM_NCRBUTTONUP:
         return SendMessageW(parentWindowHandle, uMsg, wParam, lParam);
     case WM_DESTROY: {
-        QMutexLocker locker(&g_win32Helper()->mutex);
+        const QMutexLocker locker(&g_win32Helper()->mutex);
         g_win32Helper()->fallbackTitleBarToParentWindowMapping.remove(windowId);
         if (g_win32Helper()->fallbackTitleBarToParentWindowMapping.count() < 1) {
             // According to Microsoft Docs, window classes registered by DLLs will
@@ -473,7 +473,7 @@ Q_GLOBAL_STATIC(Win32Helper, g_win32Helper)
         WARNING << "Failed to re-position the fallback title bar window.";
         return false;
     }
-    QMutexLocker locker(&g_win32Helper()->mutex);
+    const QMutexLocker locker(&g_win32Helper()->mutex);
     g_win32Helper()->data[parentWindowId].fallbackTitleBarWindowId = fallbackTitleBarWindowId;
     g_win32Helper()->fallbackTitleBarToParentWindowMapping.insert(fallbackTitleBarWindowId, parentWindowId);
     return true;
diff --git a/src/core/framelessmanager.cpp b/src/core/framelessmanager.cpp
index 21b01c4..9faaffe 100644
--- a/src/core/framelessmanager.cpp
+++ b/src/core/framelessmanager.cpp
@@ -152,25 +152,25 @@ QFont FramelessManagerPrivate::getIconFont()
 
 SystemTheme FramelessManagerPrivate::systemTheme() const
 {
-    QMutexLocker locker(&g_helper()->mutex);
+    const QMutexLocker locker(&g_helper()->mutex);
     return m_systemTheme;
 }
 
 QColor FramelessManagerPrivate::systemAccentColor() const
 {
-    QMutexLocker locker(&g_helper()->mutex);
+    const QMutexLocker locker(&g_helper()->mutex);
     return m_accentColor;
 }
 
 QString FramelessManagerPrivate::wallpaper() const
 {
-    QMutexLocker locker(&g_helper()->mutex);
+    const QMutexLocker locker(&g_helper()->mutex);
     return m_wallpaper;
 }
 
 WallpaperAspectStyle FramelessManagerPrivate::wallpaperAspectStyle() const
 {
-    QMutexLocker locker(&g_helper()->mutex);
+    const QMutexLocker locker(&g_helper()->mutex);
     return m_wallpaperAspectStyle;
 }
 
@@ -227,7 +227,7 @@ void FramelessManagerPrivate::addWindow(const SystemParameters &params)
 
 void FramelessManagerPrivate::notifySystemThemeHasChangedOrNot()
 {
-    QMutexLocker locker(&g_helper()->mutex);
+    const QMutexLocker locker(&g_helper()->mutex);
     const SystemTheme currentSystemTheme = Utils::getSystemTheme();
 #ifdef Q_OS_WINDOWS
     const DwmColorizationArea currentColorizationArea = Utils::getDwmColorizationArea();
@@ -263,7 +263,7 @@ void FramelessManagerPrivate::notifySystemThemeHasChangedOrNot()
 
 void FramelessManagerPrivate::notifyWallpaperHasChangedOrNot()
 {
-    QMutexLocker locker(&g_helper()->mutex);
+    const QMutexLocker locker(&g_helper()->mutex);
     const QString currentWallpaper = Utils::getWallpaperFilePath();
     const WallpaperAspectStyle currentWallpaperAspectStyle = Utils::getWallpaperAspectStyle();
     bool notify = false;
@@ -284,7 +284,7 @@ void FramelessManagerPrivate::notifyWallpaperHasChangedOrNot()
 
 void FramelessManagerPrivate::initialize()
 {
-    QMutexLocker locker(&g_helper()->mutex);
+    const QMutexLocker locker(&g_helper()->mutex);
     m_systemTheme = Utils::getSystemTheme();
 #ifdef Q_OS_WINDOWS
     m_colorizationArea = Utils::getDwmColorizationArea();
diff --git a/src/core/sysapiloader.cpp b/src/core/sysapiloader.cpp
index 9e626a5..40fa0c2 100644
--- a/src/core/sysapiloader.cpp
+++ b/src/core/sysapiloader.cpp
@@ -82,7 +82,7 @@ bool SysApiLoader::isAvailable(const QString &library, const QString &function)
     if (library.isEmpty() || function.isEmpty()) {
         return false;
     }
-    QMutexLocker locker(&m_mutex);
+    const QMutexLocker locker(&m_mutex);
     if (m_functionCache.contains(function)) {
         return m_functionCache.value(function).has_value();
     }
@@ -103,7 +103,7 @@ QFunctionPointer SysApiLoader::get(const QString &function)
     if (function.isEmpty()) {
         return nullptr;
     }
-    QMutexLocker locker(&m_mutex);
+    const QMutexLocker locker(&m_mutex);
     if (m_functionCache.contains(function)) {
         const std::optional<QFunctionPointer> symbol = m_functionCache.value(function);
         if (symbol.has_value()) {
diff --git a/src/core/utils.cpp b/src/core/utils.cpp
index 7c93cf0..67e566e 100644
--- a/src/core/utils.cpp
+++ b/src/core/utils.cpp
@@ -144,6 +144,8 @@ QString Utils::getSystemButtonIconCode(const SystemButtonType button)
         return QChar(icon.segoe);
     }
 #endif
+    // We always use Micon on UNIX platforms because Microsoft doesn't allow distributing
+    // the Segoe icon font to other platforms than Windows.
     return QChar(icon.micon);
 }
 
diff --git a/src/core/utils_mac.mm b/src/core/utils_mac.mm
index 8db135b..f49ab3a 100644
--- a/src/core/utils_mac.mm
+++ b/src/core/utils_mac.mm
@@ -406,7 +406,7 @@ Q_GLOBAL_STATIC(MacUtilsData, g_macUtilsData);
     if (!windowId) {
         return nil;
     }
-    QMutexLocker locker(&g_macUtilsData()->mutex);
+    const QMutexLocker locker(&g_macUtilsData()->mutex);
     if (!g_macUtilsData()->hash.contains(windowId)) {
         QWindow * const qwindow = Utils::findWindow(windowId);
         Q_ASSERT(qwindow);
diff --git a/src/core/utils_win.cpp b/src/core/utils_win.cpp
index eda156a..a2f9904 100644
--- a/src/core/utils_win.cpp
+++ b/src/core/utils_win.cpp
@@ -132,6 +132,7 @@ FRAMELESSHELPER_STRING_CONSTANT(AccentColor)
 FRAMELESSHELPER_STRING_CONSTANT(GetScaleFactorForMonitor)
 FRAMELESSHELPER_STRING_CONSTANT(WallpaperStyle)
 FRAMELESSHELPER_STRING_CONSTANT(TileWallpaper)
+FRAMELESSHELPER_STRING_CONSTANT(UnregisterClassW)
 
 struct Win32UtilsHelperData
 {
@@ -176,15 +177,15 @@ static const QHash<int, SYSTEM_METRIC> g_systemMetricsTable = {
     {SM_CXPADDEDBORDER, { 4,  5,  5,  6,  6,  6,  7,  7,  8,  9, 10, 12, 14, 16,  18,  20}}
 };
 
-template <typename T>
+template<typename T>
 class HumbleComPtr
 {
     Q_DISABLE_COPY_MOVE(HumbleComPtr)
 
 public:
-    HumbleComPtr() = default;
+    explicit HumbleComPtr() = default;
 
-    HumbleComPtr(std::nullptr_t ptr)
+    explicit HumbleComPtr(std::nullptr_t ptr)
     {
         Q_UNUSED(ptr);
     }
@@ -231,6 +232,35 @@ private:
     T *p = nullptr;
 };
 
+struct WindowClassCleaner
+{
+    explicit WindowClassCleaner(const std::wstring &name)
+    {
+        this->name = name;
+    }
+
+    ~WindowClassCleaner()
+    {
+        if (name.empty()) {
+            return;
+        }
+        const HINSTANCE instance = GetModuleHandleW(nullptr);
+        if (!instance) {
+            WARNING << Utils::getSystemErrorMessage(kGetModuleHandleW);
+            return;
+        }
+        if (UnregisterClassW(name.c_str(), instance) == FALSE) {
+            WARNING << Utils::getSystemErrorMessage(kUnregisterClassW);
+        }
+    }
+
+private:
+    Q_DISABLE_COPY_MOVE(WindowClassCleaner)
+
+private:
+    std::wstring name = {};
+};
+
 [[nodiscard]] static inline QString hkcuRegistryKey()
 {
     static const QString key = FRAMELESSHELPER_STRING_LITERAL("HKEY_CURRENT_USER");
@@ -274,6 +304,7 @@ private:
                 WARNING << Utils::getSystemErrorMessage(kRegisterClassExW);
                 return nullptr;
             }
+            static const auto cleaner = WindowClassCleaner(kDummyWindowClassName);
         }
         const HWND window = CreateWindowExW(0, kDummyWindowClassName, nullptr,
             WS_OVERLAPPEDWINDOW, 0, 0, 0, 0, nullptr, nullptr, instance, nullptr);
@@ -961,7 +992,7 @@ quint32 Utils::getPrimaryScreenDpi(const bool horizontal)
             HRESULT(WINAPI *)(D2D1_FACTORY_TYPE, REFIID, CONST D2D1_FACTORY_OPTIONS *, void **);
         const auto pD2D1CreateFactory =
             reinterpret_cast<D2D1CreateFactoryPtr>(SysApiLoader::instance()->get(kD2D1CreateFactory));
-        HumbleComPtr<ID2D1Factory> d2dFactory = nullptr;
+        auto d2dFactory = HumbleComPtr<ID2D1Factory>(nullptr);
         HRESULT hr = pD2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, __uuidof(ID2D1Factory),
                                         nullptr, reinterpret_cast<void **>(&d2dFactory));
         if (SUCCEEDED(hr)) {
@@ -1279,7 +1310,7 @@ void Utils::installSystemMenuHook(const WId windowId,
     if (!windowId || !isWindowFixedSize) {
         return;
     }
-    QMutexLocker locker(&g_utilsHelper()->mutex);
+    const QMutexLocker locker(&g_utilsHelper()->mutex);
     if (g_utilsHelper()->data.contains(windowId)) {
         return;
     }
@@ -1311,7 +1342,7 @@ void Utils::uninstallSystemMenuHook(const WId windowId)
     if (!windowId) {
         return;
     }
-    QMutexLocker locker(&g_utilsHelper()->mutex);
+    const QMutexLocker locker(&g_utilsHelper()->mutex);
     if (!g_utilsHelper()->data.contains(windowId)) {
         return;
     }
diff --git a/src/quick/framelessquickhelper.cpp b/src/quick/framelessquickhelper.cpp
index 82ba11f..2344b3d 100644
--- a/src/quick/framelessquickhelper.cpp
+++ b/src/quick/framelessquickhelper.cpp
@@ -129,7 +129,7 @@ void FramelessQuickHelperPrivate::setTitleBarItem(QQuickItem *value)
     if (!value) {
         return;
     }
-    QMutexLocker locker(&g_quickHelper()->mutex);
+    const QMutexLocker locker(&g_quickHelper()->mutex);
     QuickHelperData *data = getWindowDataMutable();
     if (!data) {
         return;
@@ -225,7 +225,7 @@ void FramelessQuickHelperPrivate::setSystemButton(QQuickItem *item, const QuickG
     if (!item || (buttonType == QuickGlobal::SystemButtonType::Unknown)) {
         return;
     }
-    QMutexLocker locker(&g_quickHelper()->mutex);
+    const QMutexLocker locker(&g_quickHelper()->mutex);
     QuickHelperData *data = getWindowDataMutable();
     if (!data) {
         return;
@@ -259,7 +259,7 @@ void FramelessQuickHelperPrivate::setHitTestVisible(QQuickItem *item, const bool
     if (!item) {
         return;
     }
-    QMutexLocker locker(&g_quickHelper()->mutex);
+    const QMutexLocker locker(&g_quickHelper()->mutex);
     QuickHelperData *data = getWindowDataMutable();
     if (!data) {
         return;
@@ -662,7 +662,7 @@ QuickHelperData FramelessQuickHelperPrivate::getWindowData() const
         return {};
     }
     const WId windowId = window->winId();
-    QMutexLocker locker(&g_quickHelper()->mutex);
+    const QMutexLocker locker(&g_quickHelper()->mutex);
     if (!g_quickHelper()->data.contains(windowId)) {
         g_quickHelper()->data.insert(windowId, {});
     }
diff --git a/src/quick/quickmicamaterial.cpp b/src/quick/quickmicamaterial.cpp
index ee68d9e..a51820e 100644
--- a/src/quick/quickmicamaterial.cpp
+++ b/src/quick/quickmicamaterial.cpp
@@ -114,7 +114,7 @@ void WallpaperImageNode::initialize()
 
 void WallpaperImageNode::maybeGenerateWallpaperImageCache(const bool force)
 {
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
     if (!m_pixmapCache.isNull() && !force) {
         return;
     }
@@ -130,7 +130,7 @@ void WallpaperImageNode::maybeGenerateWallpaperImageCache(const bool force)
 
 void WallpaperImageNode::maybeUpdateWallpaperImageClipRect()
 {
-    QMutexLocker locker(&g_data()->mutex);
+    const QMutexLocker locker(&g_data()->mutex);
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 10, 0))
     const QSizeF itemSize = m_item->size();
 #else
diff --git a/src/widgets/framelesswidgetshelper.cpp b/src/widgets/framelesswidgetshelper.cpp
index 41a8f5a..3f7d27c 100644
--- a/src/widgets/framelesswidgetshelper.cpp
+++ b/src/widgets/framelesswidgetshelper.cpp
@@ -236,7 +236,7 @@ void FramelessWidgetsHelperPrivate::setTitleBarWidget(QWidget *widget)
     if (!widget) {
         return;
     }
-    QMutexLocker locker(&g_widgetsHelper()->mutex);
+    const QMutexLocker locker(&g_widgetsHelper()->mutex);
     WidgetsHelperData *data = getWindowDataMutable();
     if (!data) {
         return;
@@ -259,7 +259,7 @@ void FramelessWidgetsHelperPrivate::setHitTestVisible(QWidget *widget, const boo
     if (!widget) {
         return;
     }
-    QMutexLocker locker(&g_widgetsHelper()->mutex);
+    const QMutexLocker locker(&g_widgetsHelper()->mutex);
     WidgetsHelperData *data = getWindowDataMutable();
     if (!data) {
         return;
@@ -378,7 +378,7 @@ WidgetsHelperData FramelessWidgetsHelperPrivate::getWindowData() const
         return {};
     }
     const WId windowId = window->winId();
-    QMutexLocker locker(&g_widgetsHelper()->mutex);
+    const QMutexLocker locker(&g_widgetsHelper()->mutex);
     if (!g_widgetsHelper()->data.contains(windowId)) {
         g_widgetsHelper()->data.insert(windowId, {});
     }
@@ -672,7 +672,7 @@ void FramelessWidgetsHelperPrivate::setSystemButton(QWidget *widget, const Syste
     if (!widget || (buttonType == SystemButtonType::Unknown)) {
         return;
     }
-    QMutexLocker locker(&g_widgetsHelper()->mutex);
+    const QMutexLocker locker(&g_widgetsHelper()->mutex);
     WidgetsHelperData *data = getWindowDataMutable();
     if (!data) {
         return;
diff --git a/tools/dpitester/main.cpp b/tools/dpitester/main.cpp
index 9b6b168..3639002 100644
--- a/tools/dpitester/main.cpp
+++ b/tools/dpitester/main.cpp
@@ -424,7 +424,7 @@ EXTERN_C int WINAPI wmain(int argc, wchar_t *argv[])
     for (int i = 0; i != DPI_COUNT; ++i) {
         const auto entry = DPI_TABLE[i];
         const auto percent = int(std::round(entry.DevicePixelRatio * double(100)));
-        text += L"    const int DPI_" + std::to_wstring(entry.DotsPerInch) + L" = 0;";
+        text += L"    int DPI_" + std::to_wstring(entry.DotsPerInch) + L" = 0;";
         text += L" // " + std::to_wstring(percent) + L"%. The scale factor for the device is "
                 + std::to_wstring(entry.DevicePixelRatio) + L"x.\n";
         if (i == (DPI_COUNT - 1)) {