14 files changed, 168 insertions, 47 deletions
diff --git a/src/corelib/io/qdirlisting.h b/src/corelib/io/qdirlisting.h
index 73a13ed611f..94aec0934fb 100644
--- a/src/corelib/io/qdirlisting.h
+++ b/src/corelib/io/qdirlisting.h
@@ -20,6 +20,7 @@ QT_BEGIN_NAMESPACE
 
 class QDirListingPrivate;
 class QFileInfo;
+class QDebug;
 class QDir;
 class QTimeZone;
 
@@ -150,6 +151,10 @@ public:
     const_iterator constBegin() const { return begin(); }
     sentinel constEnd() const { return end(); }
 
+#ifndef QT_NO_DEBUG_STREAM
+    Q_CORE_EXPORT friend QDebug operator<<(QDebug debug, QDirListing::IteratorFlags flags);
+#endif
+
 private:
     Q_DISABLE_COPY(QDirListing)
 
@@ -160,11 +165,6 @@ private:
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QDirListing::IteratorFlags)
 
-#ifndef QT_NO_DEBUG_STREAM
-class QDebug;
-Q_CORE_EXPORT QDebug operator<<(QDebug debug, QDirListing::IteratorFlags flags);
-#endif
-
 QT_END_NAMESPACE
 
 #endif // QDIRLISTING_H
diff --git a/src/corelib/kernel/qassociativeiterable.cpp b/src/corelib/kernel/qassociativeiterable.cpp
index 8a2fc63c441..bca9d43901d 100644
--- a/src/corelib/kernel/qassociativeiterable.cpp
+++ b/src/corelib/kernel/qassociativeiterable.cpp
@@ -21,7 +21,7 @@ QT_WARNING_DISABLE_DEPRECATED
 */
 QVariant QAssociativeIterator::key() const
 {
-    return QIterablePrivate::retrieveElement(
+    return QtIterablePrivate::retrieveElement(
                 metaContainer().keyMetaType(), [this](void *dataPtr) {
         metaContainer().keyAtIterator(constIterator(), dataPtr);
     });
@@ -67,7 +67,7 @@ QVariantPointer<QAssociativeIterator> QAssociativeIterator::operator->() const
 */
 QVariant QAssociativeConstIterator::key() const
 {
-    return QIterablePrivate::retrieveElement(
+    return QtIterablePrivate::retrieveElement(
                 metaContainer().keyMetaType(), [this](void *dataPtr) {
         metaContainer().keyAtConstIterator(constIterator(), dataPtr);
     });
@@ -79,7 +79,7 @@ QVariant QAssociativeConstIterator::key() const
 */
 QVariant QAssociativeConstIterator::value() const
 {
-    return QIterablePrivate::retrieveElement(
+    return QtIterablePrivate::retrieveElement(
                 metaContainer().mappedMetaType(), [this](void *dataPtr) {
         metaContainer().mappedAtConstIterator(constIterator(), dataPtr);
     });
diff --git a/src/corelib/kernel/qiterable.cpp b/src/corelib/kernel/qiterable.cpp
index ca2893e1090..b0b772d18e0 100644
--- a/src/corelib/kernel/qiterable.cpp
+++ b/src/corelib/kernel/qiterable.cpp
@@ -626,9 +626,18 @@ Q_STATIC_LOGGING_CATEGORY(lcSynthesizedIterableAccess, "qt.iterable.synthesized"
 /*!
     \internal
  */
-void QtPrivate::warnSynthesizedAccess(const char *text)
+void QtPrivate::warnSynthesizedIterableAccess(QtPrivate::SynthesizedAccessFunction function)
 {
-    qCWarning(lcSynthesizedIterableAccess, "%s", text);
+    switch (function) {
+    case QtPrivate::SynthesizedAccessFunction::IterableSize:
+        qCWarning(lcSynthesizedIterableAccess,
+                  "size() called on an iterable without native size accessor. This is slow");
+        break;
+    case QtPrivate::SynthesizedAccessFunction::SequenceAt:
+        qCWarning(lcSynthesizedIterableAccess,
+                  "at() called on an iterable without native indexed accessors. This is slow");
+        break;
+    }
 }
 
 QT_END_NAMESPACE
diff --git a/src/corelib/kernel/qiterable.h b/src/corelib/kernel/qiterable.h
index 494cec73a3f..a5a5b35924a 100644
--- a/src/corelib/kernel/qiterable.h
+++ b/src/corelib/kernel/qiterable.h
@@ -8,10 +8,6 @@
 #include <QtCore/qtypeinfo.h>
 #include <QtCore/qtaggedpointer.h>
 
-#if !defined(QT_LEAN_HEADERS) || QT_LEAN_HEADERS < 1
-#   include <QtCore/qmetacontainer.h>
-#endif
-
 QT_BEGIN_NAMESPACE
 
 namespace QtPrivate {
@@ -65,7 +61,13 @@ namespace QtPrivate {
         }
     };
 
-    Q_CORE_EXPORT void warnSynthesizedAccess(const char *text);
+    enum class SynthesizedAccessFunction: quint8
+    {
+        IterableSize,
+        SequenceAt
+    };
+
+    Q_CORE_EXPORT void warnSynthesizedIterableAccess(SynthesizedAccessFunction function);
 }
 
 template<class Iterator, typename IteratorCategory>
@@ -75,7 +77,7 @@ public:
     using iterator_category = IteratorCategory;
     QTaggedIterator(Iterator &&it) : Iterator(std::move(it))
     {
-        const auto metaContainer = this->metaContainer();
+        [[maybe_unused]] const auto metaContainer = this->metaContainer();
         if constexpr (std::is_base_of_v<std::random_access_iterator_tag, IteratorCategory>) {
             if (!metaContainer.hasRandomAccessIterator()) {
                 qFatal("You cannot use this iterator as a random access iterator");
@@ -103,8 +105,6 @@ public:
                 this->clearIterator();
             }
         }
-
-        Q_UNUSED(metaContainer); // in case none of the above apply
     }
 
     bool operator==(const QTaggedIterator &o) const { return Iterator::operator==(o); }
@@ -506,8 +506,8 @@ public:
         // We shouldn't second-guess the underlying container, so we're not synthesizing a size.
         return -1;
 #else
-        QtPrivate::warnSynthesizedAccess(
-                "size() called on an iterable without native size accessor. This is slow");
+        QtPrivate::warnSynthesizedIterableAccess(
+                QtPrivate::SynthesizedAccessFunction::IterableSize);
 
         if (!m_metaContainer.hasConstIterator())
             return -1;
diff --git a/src/corelib/kernel/qiterable_impl.h b/src/corelib/kernel/qiterable_impl.h
index 7bc06ccde15..419595a3f2c 100644
--- a/src/corelib/kernel/qiterable_impl.h
+++ b/src/corelib/kernel/qiterable_impl.h
@@ -9,7 +9,7 @@
 
 QT_BEGIN_NAMESPACE
 
-namespace QIterablePrivate {
+namespace QtIterablePrivate {
 
 template<typename Callback>
 static QVariant retrieveElement(QMetaType type, Callback callback)
@@ -24,7 +24,7 @@ static QVariant retrieveElement(QMetaType type, Callback callback)
     return v;
 }
 
-} // namespace QIterablePrivate
+} // namespace QtIterablePrivate
 
 QT_END_NAMESPACE
 
diff --git a/src/corelib/kernel/qmetaassociation.h b/src/corelib/kernel/qmetaassociation.h
index d481ae91079..d94b5191a7b 100644
--- a/src/corelib/kernel/qmetaassociation.h
+++ b/src/corelib/kernel/qmetaassociation.h
@@ -33,7 +33,7 @@ public:
     key_type key() const
     {
         const QMetaAssociation meta = metaContainer();
-        return QIterablePrivate::retrieveElement(meta.keyMetaType(), [&](void *dataPtr) {
+        return QtIterablePrivate::retrieveElement(meta.keyMetaType(), [&](void *dataPtr) {
             meta.keyAtIterator(constIterator(), dataPtr);
         });
     }
@@ -58,7 +58,7 @@ public:
     key_type key() const
     {
         const QMetaAssociation meta = metaContainer();
-        return QIterablePrivate::retrieveElement(meta.keyMetaType(), [&](void *dataPtr) {
+        return QtIterablePrivate::retrieveElement(meta.keyMetaType(), [&](void *dataPtr) {
             meta.keyAtConstIterator(constIterator(), dataPtr);
         });
     }
@@ -79,12 +79,12 @@ QVariant associativeIteratorToVariant(const Referred &referred)
     const auto metaAssociation = referred.metaContainer();
     const QMetaType metaType(metaAssociation.mappedMetaType());
     if (metaType.isValid(QT6_CALL_NEW_OVERLOAD)) {
-        return QIterablePrivate::retrieveElement(metaType, [&](void *dataPtr) {
+        return QtIterablePrivate::retrieveElement(metaType, [&](void *dataPtr) {
             metaAssociation.mappedAtConstIterator(referred.constIterator(), dataPtr);
         });
     }
 
-    return QIterablePrivate::retrieveElement(metaType, [&](void *dataPtr) {
+    return QtIterablePrivate::retrieveElement(metaType, [&](void *dataPtr) {
         metaAssociation.keyAtConstIterator(referred.constIterator(), dataPtr);
     });
 }
@@ -243,7 +243,7 @@ public:
     QVariant value(const QVariant &key) const
     {
         const QMetaAssociation meta = metaContainer();
-        return QIterablePrivate::retrieveElement(meta.mappedMetaType(), [&](void *dataPtr) {
+        return QtIterablePrivate::retrieveElement(meta.mappedMetaType(), [&](void *dataPtr) {
             QtPrivate::QVariantTypeCoercer coercer;
             meta.mappedAtKey(constIterable(), coercer.coerce(key, meta.keyMetaType()), dataPtr);
         });
diff --git a/src/corelib/kernel/qmetasequence.h b/src/corelib/kernel/qmetasequence.h
index f8052476d79..792202301e3 100644
--- a/src/corelib/kernel/qmetasequence.h
+++ b/src/corelib/kernel/qmetasequence.h
@@ -57,7 +57,7 @@ template<typename Referred>
 QVariant sequentialIteratorToVariant(const Referred &referred)
 {
     const auto metaSequence = referred.metaContainer();
-    return QIterablePrivate::retrieveElement(metaSequence.valueMetaType(), [&](void *dataPtr) {
+    return QtIterablePrivate::retrieveElement(metaSequence.valueMetaType(), [&](void *dataPtr) {
         metaSequence.valueAtConstIterator(referred.constIterator(), dataPtr);
     });
 }
@@ -178,7 +178,7 @@ public:
     QVariant at(qsizetype idx) const
     {
         const QMetaSequence meta = metaContainer();
-        return QIterablePrivate::retrieveElement(meta.valueMetaType(), [&](void *dataPtr) {
+        return QtIterablePrivate::retrieveElement(meta.valueMetaType(), [&](void *dataPtr) {
             if (meta.canGetValueAtIndex()) {
                 meta.valueAtIndex(constIterable(), idx, dataPtr);
                 return;
@@ -186,8 +186,8 @@ public:
 
 #if QT_VERSION < QT_VERSION_CHECK(7, 0, 0)
             // We shouldn't second-guess the underlying container.
-            QtPrivate::warnSynthesizedAccess(
-                    "at() called on an iterable without native indexed accessors. This is slow");
+            QtPrivate::warnSynthesizedIterableAccess(
+                    QtPrivate::SynthesizedAccessFunction::SequenceAt);
             void *it = meta.constBegin(m_iterable.constPointer());
             meta.advanceConstIterator(it, idx);
             meta.valueAtConstIterator(it, dataPtr);
diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index 565f9182e68..580e830782e 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -2524,7 +2524,7 @@ bool QMetaType::convert(QMetaType fromType, const void *from, QMetaType toType,
     if (toTypeId == qMetaTypeId<QMetaAssociation::Iterable>())
         return convertToAssociativeIterable<QMetaAssociation::Iterable>(fromType, from, to);
 
-#if QT_DEPRECATED_SINCE(6, 13)
+#if QT_DEPRECATED_SINCE(6, 15)
     QT_WARNING_PUSH
     QT_WARNING_DISABLE_DEPRECATED
 
@@ -2550,7 +2550,7 @@ bool QMetaType::convert(QMetaType fromType, const void *from, QMetaType toType,
         return convertToAssociativeIterable<QAssociativeIterable>(fromType, from, to);
 
     QT_WARNING_POP
-#endif // QT_DEPRECATED_SINCE(6, 13)
+#endif // QT_DEPRECATED_SINCE(6, 15)
 
     return convertMetaObject(fromType, from, toType, to);
 }
@@ -2578,7 +2578,7 @@ bool QMetaType::view(QMetaType fromType, void *from, QMetaType toType, void *to)
     if (toTypeId == qMetaTypeId<QMetaAssociation::Iterable>())
         return viewAsAssociativeIterable<QMetaAssociation::Iterable>(fromType, from, to);
 
-#if QT_DEPRECATED_SINCE(6, 13)
+#if QT_DEPRECATED_SINCE(6, 15)
     QT_WARNING_PUSH
     QT_WARNING_DISABLE_DEPRECATED
 
@@ -2589,7 +2589,7 @@ bool QMetaType::view(QMetaType fromType, void *from, QMetaType toType, void *to)
         return viewAsAssociativeIterable<QAssociativeIterable>(fromType, from, to);
 
     QT_WARNING_POP
-#endif // QT_DEPRECATED_SINCE(6, 13)
+#endif // QT_DEPRECATED_SINCE(6, 15)
 
     return convertMetaObject(fromType, from, toType, to);
 }
@@ -2629,7 +2629,7 @@ bool QMetaType::canView(QMetaType fromType, QMetaType toType)
     if (toTypeId == qMetaTypeId<QMetaAssociation::Iterable>())
         return canImplicitlyViewAsAssociativeIterable(fromType);
 
-#if QT_DEPRECATED_SINCE(6, 13)
+#if QT_DEPRECATED_SINCE(6, 15)
     QT_WARNING_PUSH
     QT_WARNING_DISABLE_DEPRECATED
 
@@ -2640,7 +2640,7 @@ bool QMetaType::canView(QMetaType fromType, QMetaType toType)
         return canImplicitlyViewAsAssociativeIterable(fromType);
 
     QT_WARNING_POP
-#endif
+#endif // QT_DEPRECATED_SINCE(6, 15)
 
     if (canConvertMetaObject(fromType, toType))
         return true;
@@ -2768,7 +2768,7 @@ bool QMetaType::canConvert(QMetaType fromType, QMetaType toType)
         return true;
     }
 
-#if QT_DEPRECATED_SINCE(6, 13)
+#if QT_DEPRECATED_SINCE(6, 15)
     QT_WARNING_PUSH
     QT_WARNING_DISABLE_DEPRECATED
 
@@ -2789,7 +2789,7 @@ bool QMetaType::canConvert(QMetaType fromType, QMetaType toType)
     }
 
     QT_WARNING_POP
-#endif // QT_DEPRECATED_SINCE(6, 13)
+#endif // QT_DEPRECATED_SINCE(6, 15)
 
     if (toTypeId == QVariantPair && hasRegisteredConverterFunction(
                     fromType, QMetaType::fromType<QtMetaTypePrivate::QPairVariantInterfaceImpl>()))
diff --git a/src/corelib/kernel/qsequentialiterable.cpp b/src/corelib/kernel/qsequentialiterable.cpp
index b256b129d2c..cf9c38c5338 100644
--- a/src/corelib/kernel/qsequentialiterable.cpp
+++ b/src/corelib/kernel/qsequentialiterable.cpp
@@ -211,7 +211,7 @@ QVariantPointer<QSequentialIterator> QSequentialIterator::operator->() const
 */
 QVariant QSequentialConstIterator::operator*() const
 {
-    return QIterablePrivate::retrieveElement(metaContainer().valueMetaType(), [this](void *dataPtr) {
+    return QtIterablePrivate::retrieveElement(metaContainer().valueMetaType(), [this](void *dataPtr) {
         metaContainer().valueAtConstIterator(constIterator(), dataPtr);
     });
 }
diff --git a/src/plugins/styles/modernwindows/CMakeLists.txt b/src/plugins/styles/modernwindows/CMakeLists.txt
index 985bce3a2d6..41d2797f2a2 100644
--- a/src/plugins/styles/modernwindows/CMakeLists.txt
+++ b/src/plugins/styles/modernwindows/CMakeLists.txt
@@ -17,6 +17,7 @@ qt_internal_add_plugin(QModernWindowsStylePlugin
         qwindowsthemedata.cpp qwindowsthemedata_p.h
 
     LIBRARIES
+        dwmapi
         gdi32
         user32
         uxtheme
diff --git a/src/plugins/styles/modernwindows/qwindows11style.cpp b/src/plugins/styles/modernwindows/qwindows11style.cpp
index 98e51397c17..5e5b764311b 100644
--- a/src/plugins/styles/modernwindows/qwindows11style.cpp
+++ b/src/plugins/styles/modernwindows/qwindows11style.cpp
@@ -14,6 +14,7 @@
 #include <qpainterstateguard.h>
 #include <QGraphicsDropShadowEffect>
 #include <QLatin1StringView>
+#include <QtCore/qoperatingsystemversion.h>
 #include <QtWidgets/qcombobox.h>
 #if QT_CONFIG(commandlinkbutton)
 #include <QtWidgets/qcommandlinkbutton.h>
@@ -36,8 +37,12 @@
 #if QT_CONFIG(menubar)
 #  include <QtWidgets/qmenubar.h>
 #endif
+#if QT_CONFIG(tooltip)
+#include "private/qtooltip_p.h"
+#endif
 #include "qdrawutil.h"
 #include <chrono>
+#include <dwmapi.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -47,6 +52,8 @@ static constexpr int topLevelRoundingRadius    = 8; //Radius for toplevel items
 static constexpr int secondLevelRoundingRadius = 4; //Radius for second level items like hovered menu item round corners
 static constexpr int contentItemHMargin = 4;        // margin between content items (e.g. text and icon)
 static constexpr int contentHMargin = 2 * 3;        // margin between rounded border and content (= rounded border margin * 3)
+
+
 namespace StyleOptionHelper
 {
 inline bool isChecked(const QStyleOption *option)
@@ -281,6 +288,11 @@ static qreal sliderInnerRadius(QStyle::State state, bool insideHandle)
 
   \sa QWindows11Style QWindowsVistaStyle, QMacStyle, QFusionStyle
 */
+QWindows11StylePrivate::QWindows11StylePrivate()
+{
+    nativeRoundedTopLevelWindows =
+            QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows11_21H2;
+}
 
 /*!
   Constructs a QWindows11Style object.
@@ -991,11 +1003,13 @@ void QWindows11Style::drawPrimitive(PrimitiveElement element, const QStyleOption
     case PE_FrameMenu:
         break;
     case PE_PanelMenu: {
-        const QRect rect = option->rect.marginsRemoved(QMargins(2, 2, 2, 2));
-        painter->setPen(highContrastTheme ? QPen(option->palette.windowText().color(), 2)
-                                          : winUI3Color(frameColorLight));
-        painter->setBrush(winUI3Color(menuPanelFill));
-        painter->drawRoundedRect(rect, topLevelRoundingRadius, topLevelRoundingRadius);
+        if (!d->nativeRoundedTopLevelWindows) {
+            const QRect rect = option->rect.marginsRemoved(QMargins(2, 2, 2, 2));
+            painter->setPen(highContrastTheme ? QPen(option->palette.windowText().color(), 2)
+                                              : winUI3Color(frameColorLight));
+            painter->setBrush(winUI3Color(menuPanelFill));
+            painter->drawRoundedRect(rect, topLevelRoundingRadius, topLevelRoundingRadius);
+        }
         break;
     }
     case PE_PanelLineEdit:
@@ -1027,6 +1041,8 @@ void QWindows11Style::drawPrimitive(PrimitiveElement element, const QStyleOption
         if (const auto *frame = qstyleoption_cast<const QStyleOptionFrame *>(option)) {
             const auto rect = QRectF(option->rect).marginsRemoved(QMarginsF(1.5, 1.5, 1.5, 1.5));
             if (qobject_cast<const QComboBoxPrivateContainer *>(widget)) {
+                if (d->nativeRoundedTopLevelWindows)
+                    break;
                 QPen pen;
                 if (highContrastTheme)
                     pen = QPen(option->palette.windowText().color(), 2);
@@ -2412,6 +2428,8 @@ int QWindows11Style::pixelMetric(PixelMetric metric, const QStyleOption *option,
 
 void QWindows11Style::polish(QWidget* widget)
 {
+    Q_D(QWindows11Style);
+
 #if QT_CONFIG(commandlinkbutton)
     if (!qobject_cast<QCommandLinkButton *>(widget))
 #endif // QT_CONFIG(commandlinkbutton)
@@ -2419,6 +2437,9 @@ void QWindows11Style::polish(QWidget* widget)
 
     const bool isScrollBar = qobject_cast<QScrollBar *>(widget);
     const auto comboBoxContainer = qobject_cast<const QComboBoxPrivateContainer *>(widget);
+    const auto isComboBoxContainer = !d->nativeRoundedTopLevelWindows && comboBoxContainer != nullptr;
+    const auto isMenu = !d->nativeRoundedTopLevelWindows && qobject_cast<QMenu *>(widget) != nullptr;
+
 #if QT_CONFIG(menubar)
     if (qobject_cast<QMenuBar *>(widget)) {
         constexpr int itemHeight = 32;
@@ -2428,7 +2449,12 @@ void QWindows11Style::polish(QWidget* widget)
         }
     }
 #endif
-    if (isScrollBar || qobject_cast<QMenu *>(widget) || comboBoxContainer) {
+    if (comboBoxContainer && d->nativeRoundedTopLevelWindows) {
+        auto view = comboBoxContainer->itemView();
+        if (view && view->viewport())
+            view->viewport()->setAutoFillBackground(false);
+    }
+    if (isScrollBar || isMenu || isComboBoxContainer) {
         bool wasCreated = widget->testAttribute(Qt::WA_WState_Created);
         bool layoutDirection = widget->testAttribute(Qt::WA_RightToLeft);
         widget->setAttribute(Qt::WA_OpaquePaintEvent,false);
@@ -2479,6 +2505,7 @@ void QWindows11Style::polish(QWidget* widget)
 
 void QWindows11Style::unpolish(QWidget *widget)
 {
+    Q_D(QWindows11Style);
 #if QT_CONFIG(commandlinkbutton)
     if (!qobject_cast<QCommandLinkButton *>(widget))
 #endif // QT_CONFIG(commandlinkbutton)
@@ -2490,8 +2517,18 @@ void QWindows11Style::unpolish(QWidget *widget)
         widget->setProperty("_q_original_menubar_maxheight", QVariant());
     }
 #endif
+    const bool isScrollBar = qobject_cast<QScrollBar *>(widget);
     const auto comboBoxContainer = qobject_cast<const QComboBoxPrivateContainer *>(widget);
-    if (comboBoxContainer) {
+    const auto isComboBoxContainer = !d->nativeRoundedTopLevelWindows && comboBoxContainer != nullptr;
+    const auto isMenu = !d->nativeRoundedTopLevelWindows && qobject_cast<QMenu *>(widget) != nullptr;
+
+    if (comboBoxContainer && d->nativeRoundedTopLevelWindows) {
+        auto view = comboBoxContainer->itemView();
+        // see QAbstractScrollAreaPrivate::init()
+        if (view && view->viewport())
+            view->viewport()->setAutoFillBackground(true);
+    }
+    if (isScrollBar || isMenu || isComboBoxContainer) {
         widget->setAttribute(Qt::WA_OpaquePaintEvent, true);
         widget->setAttribute(Qt::WA_TranslucentBackground, false);
         widget->setWindowFlag(Qt::FramelessWindowHint, false);
@@ -2512,6 +2549,66 @@ void QWindows11Style::unpolish(QWidget *widget)
         vp->setAttribute(Qt::WA_StyledBackground, origStyledBackground);
         vp->setProperty("_q_original_styled_background", QVariant());
     }
+    dwmSetWindowCornerPreference(widget, false);
+}
+
+void QWindows11Style::polish(QApplication *app)
+{
+    Q_D(const QWindows11Style);
+    if (d->nativeRoundedTopLevelWindows)
+        app->installEventFilter(this);
+    QWindowsVistaStyle::polish(app);
+}
+
+void QWindows11Style::unpolish(QApplication *app)
+{
+    Q_D(const QWindows11Style);
+    if (d->nativeRoundedTopLevelWindows)
+        app->removeEventFilter(this);
+    QWindowsVistaStyle::unpolish(app);
+}
+
+bool QWindows11Style::eventFilter(QObject *obj, QEvent *event)
+{
+    // QEvent::WinIdChange is to early so we have to wait for QEvent::Show
+    if (event->type() == QEvent::Show)
+        dwmSetWindowCornerPreference(qobject_cast<QWidget *>(obj), true);
+    return QWindowsVistaStyle::eventFilter(obj, event);
+}
+
+void QWindows11Style::dwmSetWindowCornerPreference(const QWidget *widget, bool bSet) const
+{
+    Q_D(const QWindows11Style);
+    if (!d->nativeRoundedTopLevelWindows)
+        return;
+#ifdef Q_CC_MSVC
+    static constexpr auto dmwmaWindowCornerPreference = DWMWA_WINDOW_CORNER_PREFERENCE;
+    static constexpr auto dwmcpRound = DWMWCP_ROUND;
+    static constexpr auto dwmcpRoundSmall = DWMWCP_ROUNDSMALL;
+    static constexpr auto dwmcpDefault = DWMWCP_DEFAULT;
+#else
+    // MinGW 13.1.0 does not provide this
+    static constexpr auto dmwmaWindowCornerPreference = 33;
+    static constexpr auto dwmcpRound = 2;
+    static constexpr auto dwmcpRoundSmall = 3;
+    static constexpr auto dwmcpDefault = 0;
+#endif
+    if (widget && widget->isWindow() && widget->testAttribute(Qt::WA_WState_Created)) {
+        const auto window = widget->windowHandle();
+        if (window && window->handle()) {
+            const auto wId = reinterpret_cast<HWND>(widget->winId());
+            if (wId != 0) {
+                const bool isToolTip =
+#if QT_CONFIG(tooltip)
+                        qobject_cast<const QTipLabel *>(widget) != nullptr;
+#else
+                        false;
+#endif
+                uint32_t pref = bSet ? (isToolTip ? dwmcpRoundSmall : dwmcpRound) : dwmcpDefault;
+                DwmSetWindowAttribute(wId, dmwmaWindowCornerPreference, &pref, sizeof(pref));
+            }
+        }
+    }
 }
 
 /*
diff --git a/src/plugins/styles/modernwindows/qwindows11style_p.h b/src/plugins/styles/modernwindows/qwindows11style_p.h
index 43a344a6ac9..cbe3a252946 100644
--- a/src/plugins/styles/modernwindows/qwindows11style_p.h
+++ b/src/plugins/styles/modernwindows/qwindows11style_p.h
@@ -90,10 +90,15 @@ public:
                            const QWidget *widget = nullptr) const override;
     QIcon standardIcon(StandardPixmap standardIcon, const QStyleOption *option = nullptr,
                        const QWidget *widget = nullptr) const override;
+    void polish(QApplication *app) override;
+    void unpolish(QApplication *app) override;
+    bool eventFilter(QObject *obj, QEvent *event) override;
+
 protected:
     QWindows11Style(QWindows11StylePrivate &dd);
 
 private:
+    void dwmSetWindowCornerPreference(const QWidget *widget, bool bSet) const;
     QColor calculateAccentColor(const QStyleOption *option) const;
     QPen borderPenControlAlt(const QStyleOption *option) const;
     enum class ControlType
@@ -122,10 +127,13 @@ private:
 class QWindows11StylePrivate : public QWindowsVistaStylePrivate {
     Q_DECLARE_PUBLIC(QWindows11Style)
 
+    QWindows11StylePrivate();
+
 protected:
     QIcon m_toolbarExtensionButton;
     QIcon m_lineEditClearButton;
     QIcon m_tabCloseButton;
+    bool nativeRoundedTopLevelWindows;
 };
 
 QT_END_NAMESPACE
diff --git a/src/plugins/styles/modernwindows/qwindowsvistastyle.cpp b/src/plugins/styles/modernwindows/qwindowsvistastyle.cpp
index 36b5d0f0143..9330106f541 100644
--- a/src/plugins/styles/modernwindows/qwindowsvistastyle.cpp
+++ b/src/plugins/styles/modernwindows/qwindowsvistastyle.cpp
@@ -4860,6 +4860,11 @@ void QWindowsVistaStyle::polish(QApplication *app)
     QWindowsStyle::polish(app);
 }
 
+void QWindowsVistaStyle::unpolish(QApplication *app)
+{
+    QWindowsStyle::unpolish(app);
+}
+
 /*!
  \internal
  */
diff --git a/src/plugins/styles/modernwindows/qwindowsvistastyle_p.h b/src/plugins/styles/modernwindows/qwindowsvistastyle_p.h
index da58e0b0fec..6f9e87307fb 100644
--- a/src/plugins/styles/modernwindows/qwindowsvistastyle_p.h
+++ b/src/plugins/styles/modernwindows/qwindowsvistastyle_p.h
@@ -60,6 +60,7 @@ public:
     void unpolish(QWidget *widget) override;
     void polish(QPalette &pal) override;
     void polish(QApplication *app) override;
+    void unpolish(QApplication *app) override;
 protected:
     QWindowsVistaStyle(QWindowsVistaStylePrivate &dd);
 private: