diff --git a/examples/quick/qml/main.qml b/examples/quick/qml/main.qml
index 75ab5d1..42c218b 100644
--- a/examples/quick/qml/main.qml
+++ b/examples/quick/qml/main.qml
@@ -35,7 +35,7 @@ Window {
     title: qsTr("Hello, World!")
     color: "#f0f0f0"
 
-    property int _flh_margin: ((window.visibility === Window.Maximized) || (window.visibility === Window.FullScreen)) ? 0 : (1 / Screen.devicePixelRatio)
+    property real _flh_margin: ((window.visibility === Window.Maximized) || (window.visibility === Window.FullScreen)) ? 0.0 : (1.0 / Screen.devicePixelRatio)
 
     FramelessHelper {
         id: framelessHelper
@@ -51,7 +51,7 @@ Window {
 
     Rectangle {
         id: titleBar
-        height: framelessHelper.titleBarHeight
+        height: framelessHelper.titleBarHeight + framelessHelper.resizeBorderHeight
         color: "transparent"
         anchors {
             top: parent.top
diff --git a/examples/widget/widget.cpp b/examples/widget/widget.cpp
index 72fbd71..feb0682 100644
--- a/examples/widget/widget.cpp
+++ b/examples/widget/widget.cpp
@@ -112,8 +112,9 @@ void Widget::paintEvent(QPaintEvent *event)
 void Widget::setupUi()
 {
     const QWindow *win = windowHandle();
+    const int resizeBorderHeight = Utilities::getSystemMetric(win, Utilities::SystemMetric::ResizeBorderHeight, false);
     const int titleBarHeight = Utilities::getSystemMetric(win, Utilities::SystemMetric::TitleBarHeight, false);
-    const QSize systemButtonSize = {qRound(titleBarHeight * 1.5), titleBarHeight};
+    const QSize systemButtonSize = {qRound(static_cast<qreal>(titleBarHeight + resizeBorderHeight) * 1.5), titleBarHeight};
     m_minimizeButton = new QPushButton(this);
     m_minimizeButton->setObjectName(QStringLiteral("MinimizeButton"));
     m_minimizeButton->setFixedSize(systemButtonSize);
diff --git a/framelesshelper.cpp b/framelesshelper.cpp
index 229baa6..5e7072a 100644
--- a/framelesshelper.cpp
+++ b/framelesshelper.cpp
@@ -67,34 +67,34 @@ bool FramelessHelper::eventFilter(QObject *object, QEvent *event)
         return false;
     }
     const auto currentWindow = qobject_cast<QWindow *>(object);
-    const int m_borderWidth = FramelessWindowsManager::getResizeBorderWidth(currentWindow);
-    const int m_borderHeight = FramelessWindowsManager::getResizeBorderHeight(currentWindow);
+    const int m_resizeBorderWidth = FramelessWindowsManager::getResizeBorderWidth(currentWindow);
+    const int m_resizeBorderHeight = FramelessWindowsManager::getResizeBorderHeight(currentWindow);
     const int m_titleBarHeight = FramelessWindowsManager::getTitleBarHeight(currentWindow);
     const bool m_resizable = FramelessWindowsManager::getResizable(currentWindow);
     const auto getWindowEdges =
-        [m_borderWidth, m_borderHeight](const QPointF &point, const int ww, const int wh) -> Qt::Edges {
-        if (point.y() <= m_borderHeight) {
-            if (point.x() <= m_borderWidth) {
+        [m_resizeBorderWidth, m_resizeBorderHeight](const QPointF &point, const int ww, const int wh) -> Qt::Edges {
+        if (point.y() <= m_resizeBorderHeight) {
+            if (point.x() <= m_resizeBorderWidth) {
                 return Qt::Edge::TopEdge | Qt::Edge::LeftEdge;
             }
-            if (point.x() >= (ww - m_borderWidth)) {
+            if (point.x() >= (ww - m_resizeBorderWidth)) {
                 return Qt::Edge::TopEdge | Qt::Edge::RightEdge;
             }
             return Qt::Edge::TopEdge;
         }
-        if (point.y() >= (wh - m_borderHeight)) {
-            if (point.x() <= m_borderWidth) {
+        if (point.y() >= (wh - m_resizeBorderHeight)) {
+            if (point.x() <= m_resizeBorderWidth) {
                 return Qt::Edge::BottomEdge | Qt::Edge::LeftEdge;
             }
-            if (point.x() >= (ww - m_borderWidth)) {
+            if (point.x() >= (ww - m_resizeBorderWidth)) {
                 return Qt::Edge::BottomEdge | Qt::Edge::RightEdge;
             }
             return Qt::Edge::BottomEdge;
         }
-        if (point.x() <= m_borderWidth) {
+        if (point.x() <= m_resizeBorderWidth) {
             return Qt::Edge::LeftEdge;
         }
-        if (point.x() >= (ww - m_borderWidth)) {
+        if (point.x() >= (ww - m_resizeBorderWidth)) {
             return Qt::Edge::RightEdge;
         }
         return {};
@@ -116,12 +116,13 @@ bool FramelessHelper::eventFilter(QObject *object, QEvent *event)
         }
         return Qt::CursorShape::ArrowCursor;
     };
-    const auto isInTitlebarArea = [m_titleBarHeight](const QPointF &point, const QWindow *window) -> bool {
+    const auto isInTitlebarArea = [m_resizeBorderHeight, m_titleBarHeight](const QPointF &point, const QWindow *window) -> bool {
         Q_ASSERT(window);
         if (!window) {
             return false;
         }
-        return (point.y() <= m_titleBarHeight) && !Utilities::isHitTestVisibleInChrome(window);
+        return (point.y() > m_resizeBorderHeight) && (point.y() <= (m_titleBarHeight + m_resizeBorderHeight))
+                && !Utilities::isHitTestVisibleInChrome(window);
     };
     const auto moveOrResize =
         [m_resizable, &getWindowEdges, &isInTitlebarArea](const QPointF &point, QWindow *window) {
diff --git a/framelesshelper_global.h b/framelesshelper_global.h
index b398d86..b9e4982 100644
--- a/framelesshelper_global.h
+++ b/framelesshelper_global.h
@@ -57,11 +57,18 @@
 #define FRAMELESSHELPER_USE_UNIX_VERSION
 #endif
 
-namespace _flh_global {
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
+#define Q_NODISCARD [[nodiscard]]
+#else
+#define Q_NODISCARD
+#endif
+
+namespace _flh_global
+{
 
 [[maybe_unused]] const char _flh_framelessEnabled_flag[] = "_FRAMELESSHELPER_FRAMELESS_MODE_ENABLED";
-[[maybe_unused]] const char _flh_borderWidth_flag[] = "_FRAMELESSHELPER_WINDOW_RESIZE_BORDER_WIDTH";
-[[maybe_unused]] const char _flh_borderHeight_flag[] = "_FRAMELESSHELPER_WINDOW_RESIZE_BORDER_HEIGHT";
+[[maybe_unused]] const char _flh_resizeBorderWidth_flag[] = "_FRAMELESSHELPER_WINDOW_RESIZE_BORDER_WIDTH";
+[[maybe_unused]] const char _flh_resizeBorderHeight_flag[] = "_FRAMELESSHELPER_WINDOW_RESIZE_BORDER_HEIGHT";
 [[maybe_unused]] const char _flh_titleBarHeight_flag[] = "_FRAMELESSHELPER_WINDOW_TITLE_BAR_HEIGHT";
 [[maybe_unused]] const char _flh_hitTestVisibleInChrome_flag[] = "_FRAMELESSHELPER_HIT_TEST_VISIBLE_IN_CHROME";
 [[maybe_unused]] const char _flh_useNativeTitleBar_flag[] = "_FRAMELESSHELPER_USE_NATIVE_TITLE_BAR";
diff --git a/framelesshelper_win32.cpp b/framelesshelper_win32.cpp
index d6e42c9..e81819e 100644
--- a/framelesshelper_win32.cpp
+++ b/framelesshelper_win32.cpp
@@ -109,8 +109,8 @@ static inline void installHelper(QWindow *window, const bool enable)
         return;
     }
     Utilities::updateQtFrameMargins(window, enable);
-    Utilities::updateFrameMargins(window, !enable);
-    Utilities::triggerFrameChange(window);
+    Utilities::updateFrameMargins(window->winId(), !enable);
+    Utilities::triggerFrameChange(window->winId());
     window->setProperty(_flh_global::_flh_framelessEnabled_flag, enable);
 }
 
@@ -273,13 +273,13 @@ bool FramelessHelperWin::nativeEventFilter(const QByteArray &eventType, void *me
             // The value of border width and border height should be
             // identical in most cases, when the scale factor is 1.0, it
             // should be eight pixels.
-            const int bh = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderHeight, true);
-            clientRect->top += bh;
+            const int rbh = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderHeight, true);
+            clientRect->top += rbh;
             if (!shouldHaveWindowFrame()) {
-                clientRect->bottom -= bh;
-                const int bw = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderWidth, true);
-                clientRect->left += bw;
-                clientRect->right -= bw;
+                clientRect->bottom -= rbh;
+                const int rbw = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderWidth, true);
+                clientRect->left += rbw;
+                clientRect->right -= rbw;
             }
             nonClientAreaExists = true;
         }
@@ -518,10 +518,11 @@ bool FramelessHelperWin::nativeEventFilter(const QByteArray &eventType, void *me
         POINT winLocalMouse = {qRound(globalMouse.x()), qRound(globalMouse.y())};
         ScreenToClient(msg->hwnd, &winLocalMouse);
         const QPointF localMouse = {static_cast<qreal>(winLocalMouse.x), static_cast<qreal>(winLocalMouse.y)};
-        const int bh = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderHeight, true);
+        const int rbh = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderHeight, true);
         const int tbh = getSystemMetric(window, Utilities::SystemMetric::TitleBarHeight, true);
-        const bool isTitleBar = (localMouse.y() <= tbh) && !Utilities::isHitTestVisibleInChrome(window);
-        const bool isTop = localMouse.y() <= bh;
+        const bool isTitleBar = (localMouse.y() > rbh) && (localMouse.y() <= (rbh + tbh))
+                && !Utilities::isHitTestVisibleInChrome(window);
+        const bool isTop = localMouse.y() <= rbh;
         if (shouldHaveWindowFrame()) {
             // This will handle the left, right and bottom parts of the frame
             // because we didn't change them.
@@ -547,23 +548,23 @@ bool FramelessHelperWin::nativeEventFilter(const QByteArray &eventType, void *me
             return true;
         } else {
             const auto getHitTestResult =
-                [msg, isTitleBar, &localMouse, bh, isTop, window]() -> LRESULT {
+                [msg, isTitleBar, &localMouse, rbh, isTop, window]() -> LRESULT {
                 RECT clientRect = {0, 0, 0, 0};
                 GetClientRect(msg->hwnd, &clientRect);
                 const LONG ww = clientRect.right;
                 const LONG wh = clientRect.bottom;
-                const int bw = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderWidth, true);
+                const int rbw = getSystemMetric(window, Utilities::SystemMetric::ResizeBorderWidth, true);
                 if (IsMaximized(msg->hwnd)) {
                     if (isTitleBar) {
                         return HTCAPTION;
                     }
                     return HTCLIENT;
                 }
-                const bool isBottom = (localMouse.y() >= (wh - bh));
+                const bool isBottom = (localMouse.y() >= (wh - rbh));
                 // Make the border a little wider to let the user easy to resize on corners.
-                const int factor = (isTop || isBottom) ? 2 : 1;
-                const bool isLeft = (localMouse.x() <= (bw * factor));
-                const bool isRight = (localMouse.x() >= (ww - (bw * factor)));
+                const qreal factor = (isTop || isBottom) ? 2.0 : 1.0;
+                const bool isLeft = (localMouse.x() <= qRound(static_cast<qreal>(rbw) * factor));
+                const bool isRight = (localMouse.x() >= (ww - qRound(static_cast<qreal>(rbw) * factor)));
                 const bool fixedSize = Utilities::isWindowFixedSize(window);
                 const auto getBorderValue = [fixedSize](int value) -> int {
                     return fixedSize ? HTCLIENT : value;
@@ -613,10 +614,10 @@ bool FramelessHelperWin::nativeEventFilter(const QByteArray &eventType, void *me
         // Prevent Windows from drawing the default title bar by temporarily
         // toggling the WS_VISIBLE style.
         SetWindowLongPtrW(msg->hwnd, GWL_STYLE, oldStyle & ~WS_VISIBLE);
-        Utilities::triggerFrameChange(window);
+        Utilities::triggerFrameChange(reinterpret_cast<WId>(msg->hwnd));
         const LRESULT ret = DefWindowProcW(msg->hwnd, msg->message, msg->wParam, msg->lParam);
         SetWindowLongPtrW(msg->hwnd, GWL_STYLE, oldStyle);
-        Utilities::triggerFrameChange(window);
+        Utilities::triggerFrameChange(reinterpret_cast<WId>(msg->hwnd));
         *result = ret;
         return true;
     }
diff --git a/framelessquickhelper.cpp b/framelessquickhelper.cpp
index 72d133c..3cce28a 100644
--- a/framelessquickhelper.cpp
+++ b/framelessquickhelper.cpp
@@ -30,37 +30,37 @@ FramelessQuickHelper::FramelessQuickHelper(QQuickItem *parent) : QQuickItem(pare
 {
 }
 
-int FramelessQuickHelper::resizeBorderWidth() const
+qreal FramelessQuickHelper::resizeBorderWidth() const
 {
     return FramelessWindowsManager::getResizeBorderWidth(window());
 }
 
-void FramelessQuickHelper::setResizeBorderWidth(const int val)
+void FramelessQuickHelper::setResizeBorderWidth(const qreal val)
 {
-    FramelessWindowsManager::setResizeBorderWidth(window(), val);
-    Q_EMIT resizeBorderWidthChanged();
+    FramelessWindowsManager::setResizeBorderWidth(window(), qRound(val));
+    Q_EMIT resizeBorderWidthChanged(val);
 }
 
-int FramelessQuickHelper::resizeBorderHeight() const
+qreal FramelessQuickHelper::resizeBorderHeight() const
 {
     return FramelessWindowsManager::getResizeBorderHeight(window());
 }
 
-void FramelessQuickHelper::setResizeBorderHeight(const int val)
+void FramelessQuickHelper::setResizeBorderHeight(const qreal val)
 {
-    FramelessWindowsManager::setResizeBorderHeight(window(), val);
-    Q_EMIT resizeBorderHeightChanged();
+    FramelessWindowsManager::setResizeBorderHeight(window(), qRound(val));
+    Q_EMIT resizeBorderHeightChanged(val);
 }
 
-int FramelessQuickHelper::titleBarHeight() const
+qreal FramelessQuickHelper::titleBarHeight() const
 {
     return FramelessWindowsManager::getTitleBarHeight(window());
 }
 
-void FramelessQuickHelper::setTitleBarHeight(const int val)
+void FramelessQuickHelper::setTitleBarHeight(const qreal val)
 {
-    FramelessWindowsManager::setTitleBarHeight(window(), val);
-    Q_EMIT titleBarHeightChanged();
+    FramelessWindowsManager::setTitleBarHeight(window(), qRound(val));
+    Q_EMIT titleBarHeightChanged(val);
 }
 
 bool FramelessQuickHelper::resizable() const
@@ -71,7 +71,7 @@ bool FramelessQuickHelper::resizable() const
 void FramelessQuickHelper::setResizable(const bool val)
 {
     FramelessWindowsManager::setResizable(window(), val);
-    Q_EMIT resizableChanged();
+    Q_EMIT resizableChanged(val);
 }
 
 void FramelessQuickHelper::removeWindowFrame()
diff --git a/framelessquickhelper.h b/framelessquickhelper.h
index 3502d05..98ef01e 100644
--- a/framelessquickhelper.h
+++ b/framelessquickhelper.h
@@ -34,36 +34,36 @@ class FRAMELESSHELPER_API FramelessQuickHelper : public QQuickItem
 #ifdef QML_NAMED_ELEMENT
     QML_NAMED_ELEMENT(FramelessHelper)
 #endif
-    Q_PROPERTY(int resizeBorderWidth READ resizeBorderWidth WRITE setResizeBorderWidth NOTIFY resizeBorderWidthChanged)
-    Q_PROPERTY(int resizeBorderHeight READ resizeBorderHeight WRITE setResizeBorderHeight NOTIFY resizeBorderHeightChanged)
-    Q_PROPERTY(int titleBarHeight READ titleBarHeight WRITE setTitleBarHeight NOTIFY titleBarHeightChanged)
+    Q_PROPERTY(qreal resizeBorderWidth READ resizeBorderWidth WRITE setResizeBorderWidth NOTIFY resizeBorderWidthChanged)
+    Q_PROPERTY(qreal resizeBorderHeight READ resizeBorderHeight WRITE setResizeBorderHeight NOTIFY resizeBorderHeightChanged)
+    Q_PROPERTY(qreal titleBarHeight READ titleBarHeight WRITE setTitleBarHeight NOTIFY titleBarHeightChanged)
     Q_PROPERTY(bool resizable READ resizable WRITE setResizable NOTIFY resizableChanged)
 
 public:
     explicit FramelessQuickHelper(QQuickItem *parent = nullptr);
     ~FramelessQuickHelper() override = default;
 
-    [[nodiscard]] int resizeBorderWidth() const;
-    void setResizeBorderWidth(const int val);
+    Q_NODISCARD qreal resizeBorderWidth() const;
+    void setResizeBorderWidth(const qreal val);
 
-    [[nodiscard]] int resizeBorderHeight() const;
-    void setResizeBorderHeight(const int val);
+    Q_NODISCARD qreal resizeBorderHeight() const;
+    void setResizeBorderHeight(const qreal val);
 
-    [[nodiscard]] int titleBarHeight() const;
-    void setTitleBarHeight(const int val);
+    Q_NODISCARD qreal titleBarHeight() const;
+    void setTitleBarHeight(const qreal val);
 
-    [[nodiscard]] bool resizable() const;
+    Q_NODISCARD bool resizable() const;
     void setResizable(const bool val);
 
 public Q_SLOTS:
     void removeWindowFrame();
     void bringBackWindowFrame();
-    [[nodiscard]] bool isWindowFrameless() const;
+    Q_NODISCARD bool isWindowFrameless() const;
     void setHitTestVisibleInChrome(QQuickItem *item, const bool visible);
 
 Q_SIGNALS:
-    void resizeBorderWidthChanged();
-    void resizeBorderHeightChanged();
-    void titleBarHeightChanged();
-    void resizableChanged();
+    void resizeBorderWidthChanged(qreal);
+    void resizeBorderHeightChanged(qreal);
+    void titleBarHeightChanged(qreal);
+    void resizableChanged(bool);
 };
diff --git a/framelesswindowsmanager.cpp b/framelesswindowsmanager.cpp
index 47ced69..9ea6c55 100644
--- a/framelesswindowsmanager.cpp
+++ b/framelesswindowsmanager.cpp
@@ -91,7 +91,7 @@ int FramelessWindowsManager::getResizeBorderWidth(const QWindow *window)
         return 8;
     }
 #ifdef FRAMELESSHELPER_USE_UNIX_VERSION
-    const int value = window->property(_flh_global::_flh_borderWidth_flag).toInt();
+    const int value = window->property(_flh_global::_flh_resizeBorderWidth_flag).toInt();
     return value <= 0 ? 8 : value;
 #else
     return Utilities::getSystemMetric(window, Utilities::SystemMetric::ResizeBorderWidth, false);
@@ -104,7 +104,7 @@ void FramelessWindowsManager::setResizeBorderWidth(QWindow *window, const int va
     if (!window || (value <= 0)) {
         return;
     }
-    window->setProperty(_flh_global::_flh_borderWidth_flag, value);
+    window->setProperty(_flh_global::_flh_resizeBorderWidth_flag, value);
 }
 
 int FramelessWindowsManager::getResizeBorderHeight(const QWindow *window)
@@ -114,7 +114,7 @@ int FramelessWindowsManager::getResizeBorderHeight(const QWindow *window)
         return 8;
     }
 #ifdef FRAMELESSHELPER_USE_UNIX_VERSION
-    const int value = window->property(_flh_global::_flh_borderHeight_flag).toInt();
+    const int value = window->property(_flh_global::_flh_resizeBorderHeight_flag).toInt();
     return value <= 0 ? 8 : value;
 #else
     return Utilities::getSystemMetric(window, Utilities::SystemMetric::ResizeBorderHeight, false);
@@ -127,18 +127,18 @@ void FramelessWindowsManager::setResizeBorderHeight(QWindow *window, const int v
     if (!window || (value <= 0)) {
         return;
     }
-    window->setProperty(_flh_global::_flh_borderHeight_flag, value);
+    window->setProperty(_flh_global::_flh_resizeBorderHeight_flag, value);
 }
 
 int FramelessWindowsManager::getTitleBarHeight(const QWindow *window)
 {
     Q_ASSERT(window);
     if (!window) {
-        return 31;
+        return 23;
     }
 #ifdef FRAMELESSHELPER_USE_UNIX_VERSION
     const int value = window->property(_flh_global::_flh_titleBarHeight_flag).toInt();
-    return value <= 0 ? 31 : value;
+    return value <= 0 ? 23 : value;
 #else
     return Utilities::getSystemMetric(window, Utilities::SystemMetric::TitleBarHeight, false);
 #endif
diff --git a/utilities.h b/utilities.h
index 474fdc3..787b2a5 100644
--- a/utilities.h
+++ b/utilities.h
@@ -49,8 +49,8 @@ enum class SystemMetric
 [[nodiscard]] FRAMELESSHELPER_API bool isWin8Point1OrGreater();
 [[nodiscard]] FRAMELESSHELPER_API bool isWin10OrGreater();
 [[nodiscard]] FRAMELESSHELPER_API bool isDwmCompositionAvailable();
-FRAMELESSHELPER_API void triggerFrameChange(const QWindow *window);
-FRAMELESSHELPER_API void updateFrameMargins(const QWindow *window, const bool reset);
+FRAMELESSHELPER_API void triggerFrameChange(const WId winId);
+FRAMELESSHELPER_API void updateFrameMargins(const WId winId, const bool reset);
 FRAMELESSHELPER_API void updateQtFrameMargins(QWindow *window, const bool enable);
 #endif
 
diff --git a/utilities_win32.cpp b/utilities_win32.cpp
index 336cc3b..51a9c43 100644
--- a/utilities_win32.cpp
+++ b/utilities_win32.cpp
@@ -47,7 +47,7 @@ Q_DECLARE_METATYPE(QMargins)
 #endif
 
 // The standard values of resize border width, resize border height and title bar height when DPI is 96.
-static const int g_defaultResizeBorderWidth = 8, g_defaultResizeBorderHeight = 8, g_defaultTitleBarHeight = 31;
+static const int g_defaultResizeBorderWidth = 8, g_defaultResizeBorderHeight = 8, g_defaultTitleBarHeight = 23;
 
 bool Utilities::isDwmCompositionAvailable()
 {
@@ -71,9 +71,9 @@ int Utilities::getSystemMetric(const QWindow *window, const SystemMetric metric,
     }
     switch (metric) {
     case SystemMetric::ResizeBorderWidth: {
-        const int bw = window->property(_flh_global::_flh_borderWidth_flag).toInt();
-        if ((bw > 0) && !forceSystemValue) {
-            return qRound(static_cast<qreal>(bw) * (dpiScale ? window->devicePixelRatio() : 1.0));
+        const int rbw = window->property(_flh_global::_flh_resizeBorderWidth_flag).toInt();
+        if ((rbw > 0) && !forceSystemValue) {
+            return qRound(static_cast<qreal>(rbw) * (dpiScale ? window->devicePixelRatio() : 1.0));
         } else {
             const int result = GetSystemMetrics(SM_CXSIZEFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
             if (result > 0) {
@@ -92,9 +92,9 @@ int Utilities::getSystemMetric(const QWindow *window, const SystemMetric metric,
         }
     }
     case SystemMetric::ResizeBorderHeight: {
-        const int bh = window->property(_flh_global::_flh_borderHeight_flag).toInt();
-        if ((bh > 0) && !forceSystemValue) {
-            return qRound(static_cast<qreal>(bh) * (dpiScale ? window->devicePixelRatio() : 1.0));
+        const int rbh = window->property(_flh_global::_flh_resizeBorderHeight_flag).toInt();
+        if ((rbh > 0) && !forceSystemValue) {
+            return qRound(static_cast<qreal>(rbh) * (dpiScale ? window->devicePixelRatio() : 1.0));
         } else {
             // There is no "SM_CYPADDEDBORDER".
             const int result = GetSystemMetrics(SM_CYSIZEFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
@@ -118,8 +118,7 @@ int Utilities::getSystemMetric(const QWindow *window, const SystemMetric metric,
         if ((tbh > 0) && !forceSystemValue) {
             return qRound(static_cast<qreal>(tbh) * (dpiScale ? window->devicePixelRatio() : 1.0));
         } else {
-            // There is no "SM_CYPADDEDBORDER".
-            const int result = GetSystemMetrics(SM_CYCAPTION) + GetSystemMetrics(SM_CYSIZEFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
+            const int result = GetSystemMetrics(SM_CYCAPTION);
             if (result > 0) {
                 if (dpiScale) {
                     return result;
@@ -139,30 +138,30 @@ int Utilities::getSystemMetric(const QWindow *window, const SystemMetric metric,
     return 0;
 }
 
-void Utilities::triggerFrameChange(const QWindow *window)
+void Utilities::triggerFrameChange(const WId winId)
 {
-    Q_ASSERT(window);
-    if (!window) {
+    Q_ASSERT(winId);
+    if (!winId) {
         return;
     }
-    const auto hwnd = reinterpret_cast<HWND>(window->winId());
+    const auto hwnd = reinterpret_cast<HWND>(winId);
     if (SetWindowPos(hwnd, nullptr, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOACTIVATE | SWP_NOSIZE | SWP_NOMOVE | SWP_NOZORDER | SWP_NOOWNERZORDER) == FALSE) {
         qWarning() << "SetWindowPos() failed.";
     }
 }
 
-void Utilities::updateFrameMargins(const QWindow *window, const bool reset)
+void Utilities::updateFrameMargins(const WId winId, const bool reset)
 {
     // DwmExtendFrameIntoClientArea() will always fail if DWM Composition is disabled.
     // No need to try in this case.
     if (!isDwmCompositionAvailable()) {
         return;
     }
-    Q_ASSERT(window);
-    if (!window) {
+    Q_ASSERT(winId);
+    if (!winId) {
         return;
     }
-    const auto hwnd = reinterpret_cast<HWND>(window->winId());
+    const auto hwnd = reinterpret_cast<HWND>(winId);
     const MARGINS margins = reset ? MARGINS{0, 0, 0, 0} : MARGINS{1, 1, 1, 1};
     if (FAILED(DwmExtendFrameIntoClientArea(hwnd, &margins))) {
         qWarning() << "DwmExtendFrameIntoClientArea() failed.";
@@ -176,9 +175,9 @@ void Utilities::updateQtFrameMargins(QWindow *window, const bool enable)
         return;
     }
     const int tbh = enable ? Utilities::getSystemMetric(window, Utilities::SystemMetric::TitleBarHeight, true, true) : 0;
-    const int bw = enable ? Utilities::getSystemMetric(window, Utilities::SystemMetric::ResizeBorderWidth, true, true) : 0;
-    const int bh = enable ? Utilities::getSystemMetric(window, Utilities::SystemMetric::ResizeBorderHeight, true, true) : 0;
-    const QMargins margins = {-bw, -tbh, -bw, -bh}; // left, top, right, bottom
+    const int rbw = enable ? Utilities::getSystemMetric(window, Utilities::SystemMetric::ResizeBorderWidth, true, true) : 0;
+    const int rbh = enable ? Utilities::getSystemMetric(window, Utilities::SystemMetric::ResizeBorderHeight, true, true) : 0;
+    const QMargins margins = {-rbw, -(rbh + tbh), -rbw, -rbh}; // left, top, right, bottom
     const QVariant marginsVar = QVariant::fromValue(margins);
     window->setProperty("_q_windowsCustomMargins", marginsVar);
 #if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))