Fix native child widget (#133)

SineStriker

2024-09-10 061951346e6bafbfd28de2e0440342dd6caca1c7

 src/core/contexts/win32windowcontext.cpp

@@ -6,13 +6,16 @@

#include <optional>

#include <QtCore/QAbstractEventDispatcher>
#include <QtCore/QDateTime>
#include <QtCore/QHash>
#include <QtCore/QScopeGuard>
#include <QtCore/QTimer>
#include <QtCore/QDateTime>
#include <QtGui/QGuiApplication>
#include <QtGui/QPainter>
#include <QtGui/QPalette>

#include <QtGui/qpa/qwindowsysteminterface.h>

#include <QtGui/private/qhighdpiscaling_p.h>
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
@@ -31,6 +34,12 @@
#include "qwkwindowsextra_p.h"

namespace QWK {

    enum IconButtonClickLevelFlag {
        IconButtonClicked = 1,
        IconButtonDoubleClicked = 2,
        IconButtonTriggersClose = 4,
    };

    // The thickness of an auto-hide taskbar in pixels.
    static constexpr const quint8 kAutoHideTaskBarThickness = 2;
@@ -72,6 +81,8 @@

    static void setInternalWindowFrameMargins(QWindow *window, const QMargins &margins) {
        const QVariant marginsVar = QVariant::fromValue(margins);

        // TODO: Add comments
        window->setProperty("_q_windowsCustomMargins", marginsVar);
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
        if (QPlatformWindow *platformWindow = window->handle()) {
@@ -115,6 +126,36 @@
                       SWP_NOACTIVATE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER);
    }

    static inline bool isFullScreen(HWND hwnd) {
        RECT windowRect{};
        ::GetWindowRect(hwnd, &windowRect);
        // Compare to the full area of the screen, not the work area.
        return (windowRect == getMonitorForWindow(hwnd).rcMonitor);
    }

    static inline bool isMaximized(HWND hwnd) {
        return ::IsZoomed(hwnd);
    }

    static inline bool isMinimized(HWND hwnd) {
        return ::IsIconic(hwnd);
    }

    static inline bool isWindowNoState(HWND hwnd) {
#if 0
        WINDOWPLACEMENT wp{};
        wp.length = sizeof(wp);
        ::GetWindowPlacement(hwnd, &wp);
        return ((wp.showCmd == SW_NORMAL) || (wp.showCmd == SW_RESTORE));
#else
        if (isFullScreen(hwnd)) {
            return false;
        }
        const auto style = static_cast<DWORD>(::GetWindowLongPtrW(hwnd, GWL_STYLE));
        return (!(style & (WS_MINIMIZE | WS_MAXIMIZE)));
#endif
    }

    static inline void bringWindowToFront(HWND hwnd) {
        HWND oldForegroundWindow = ::GetForegroundWindow();
        if (!oldForegroundWindow) {
@@ -126,7 +167,7 @@
        if (!::IsWindowVisible(hwnd)) {
            ::ShowWindow(hwnd, SW_SHOW);
        }
        if (IsMinimized(hwnd)) {
        if (isMinimized(hwnd)) {
            // Restore the window if it is minimized.
            ::ShowWindow(hwnd, SW_RESTORE);
            // Once we've been restored, throw us on the active monitor.
@@ -153,7 +194,7 @@
        [[maybe_unused]] const auto &cleaner =
            qScopeGuard([windowThreadProcessId, currentThreadId]() {
                ::AttachThreadInput(windowThreadProcessId, currentThreadId, FALSE); //
            });
            }); // TODO: Remove it

        ::BringWindowToTop(hwnd);
        // Activate the window too. This will force us to the virtual desktop this
@@ -161,28 +202,6 @@
        ::SetActiveWindow(hwnd);
        // Throw us on the active monitor.
        moveWindowToMonitor(hwnd, activeMonitor);
    }

    static inline bool isFullScreen(HWND hwnd) {
        RECT windowRect{};
        ::GetWindowRect(hwnd, &windowRect);
        // Compare to the full area of the screen, not the work area.
        return (windowRect == getMonitorForWindow(hwnd).rcMonitor);
    }

    static inline bool isWindowNoState(HWND hwnd) {
#if 0
        WINDOWPLACEMENT wp{};
        wp.length = sizeof(wp);
        ::GetWindowPlacement(hwnd, &wp);
        return ((wp.showCmd == SW_NORMAL) || (wp.showCmd == SW_RESTORE));
#else
        if (isFullScreen(hwnd)) {
            return false;
        }
        const auto style = static_cast<DWORD>(::GetWindowLongPtrW(hwnd, GWL_STYLE));
        return (!(style & (WS_MINIMIZE | WS_MAXIMIZE)));
#endif
    }

    static void syncPaintEventWithDwm() {
@@ -230,17 +249,18 @@
        apis.ptimeEndPeriod(ms_granularity);
    }

    static void showSystemMenu2(HWND hWnd, const POINT &pos, const bool selectFirstEntry,
                                const bool fixedSize) {
    // Returns false if the menu is canceled
    static bool showSystemMenu_sys(HWND hWnd, const POINT &pos, const bool selectFirstEntry,
                                   const bool fixedSize) {
        HMENU hMenu = ::GetSystemMenu(hWnd, FALSE);
        if (!hMenu) {
            // The corresponding window doesn't have a system menu, most likely due to the
            // lack of the "WS_SYSMENU" window style. This situation should not be treated
            // as an error so just ignore it and return early.
            return;
            return true;
        }

        const bool maxOrFull = IsMaximized(hWnd) || isFullScreen(hWnd);
        const bool maxOrFull = isMaximized(hWnd) || isFullScreen(hWnd);
        ::EnableMenuItem(hMenu, SC_CLOSE, (MF_BYCOMMAND | MFS_ENABLED));
        ::EnableMenuItem(hMenu, SC_MAXIMIZE,
                         (MF_BYCOMMAND | ((maxOrFull || fixedSize) ? MFS_DISABLED : MFS_ENABLED)));
@@ -281,7 +301,8 @@
        // Popup the system menu at the required position.
        const auto result = ::TrackPopupMenu(
            hMenu,
            (TPM_RETURNCMD | (QGuiApplication::isRightToLeft() ? TPM_RIGHTALIGN : TPM_LEFTALIGN)),
            (TPM_RETURNCMD | (QGuiApplication::isRightToLeft() ? TPM_RIGHTALIGN : TPM_LEFTALIGN) |
             TPM_RIGHTBUTTON),
            pos.x, pos.y, 0, hWnd, nullptr);

        // Unhighlight the first menu item after the popup menu is closed, otherwise it will keep
@@ -290,11 +311,12 @@

        if (!result) {
            // The user canceled the menu, no need to continue.
            return;
            return false;
        }

        // Send the command that the user chooses to the corresponding window.
        ::PostMessageW(hWnd, WM_SYSCOMMAND, result, 0);
        return true;
    }

    static inline Win32WindowContext::WindowPart getHitWindowPart(int hitTestResult) {
@@ -321,7 +343,6 @@
            case HTBORDER:
                return Win32WindowContext::FixedBorder;
            default:
                Q_UNREACHABLE();
                break;
        }
        return Win32WindowContext::Outside;
@@ -441,9 +462,12 @@
        return false;
    }

    static inline bool forwardFilteredEvents(QWindow *window, HWND hWnd, UINT message,
                                             WPARAM wParam, LPARAM lParam, LRESULT *result) {
    static inline bool forwardFilteredEvent(QWindow *window, HWND hWnd, UINT message, WPARAM wParam,
                                            LPARAM lParam, LRESULT *result) {
        MSG msg = createMessageBlock(hWnd, message, wParam, lParam);

        // https://github.com/qt/qtbase/blob/e26a87f1ecc40bc8c6aa5b889fce67410a57a702/src/plugins/platforms/windows/qwindowscontext.cpp#L1025
        // Do exact the same as what Qt Windows plugin does.

        // Run the native event filters. QTBUG-67095: Exclude input messages which are sent
        // by QEventDispatcherWin32::processEvents()
@@ -476,17 +500,38 @@
                return false;
            }

            // https://github.com/qt/qtbase/blob/e26a87f1ecc40bc8c6aa5b889fce67410a57a702/src/plugins/platforms/windows/qwindowscontext.cpp#L1546
            // Qt needs to refer to the WM_NCCALCSIZE message data that hasn't been processed, so we
            // have to process it after Qt acquires the initial data.
            auto msg = static_cast<const MSG *>(message);
            if (msg->message == WM_NCCALCSIZE && lastMessageContext) {
                LRESULT res;
                if (lastMessageContext->nonClientCalcSizeHandler(msg->hwnd, msg->message,
                                                                 msg->wParam, msg->lParam, &res)) {
                    *result = decltype(*result)(res);
                    return true;
            switch (msg->message) {
                case WM_NCCALCSIZE: {
                    // https://github.com/qt/qtbase/blob/e26a87f1ecc40bc8c6aa5b889fce67410a57a702/src/plugins/platforms/windows/qwindowscontext.cpp#L1546
                    // Qt needs to refer to the WM_NCCALCSIZE message data that hasn't been
                    // processed, so we have to process it after Qt acquires the initial data.
                    if (lastMessageContext) {
                        LRESULT res;
                        if (lastMessageContext->nonClientCalcSizeHandler(
                                msg->hwnd, msg->message, msg->wParam, msg->lParam, &res)) {
                            *result = decltype(*result)(res);
                            return true;
                        }
                    }
                    break;
                }

                    // case WM_NCHITTEST: {
                    //     // The child window must return HTTRANSPARENT when processing
                    //     WM_NCHITTEST for
                    //     // the parent window to receive WM_NCHITTEST.
                    //     if (!lastMessageContext) {
                    //         auto rootHWnd = ::GetAncestor(msg->hwnd, GA_ROOT);
                    //         if (rootHWnd != msg->hwnd) {
                    //             if (auto ctx = g_wndProcHash->value(rootHWnd)) {
                    //                 *result = HTTRANSPARENT;
                    //                 return true;
                    //             }
                    //         }
                    //     }
                    //     break;
                    // }
            }
            return false;
        }
@@ -575,22 +620,25 @@
            return ::DefWindowProcW(hWnd, message, wParam, lParam);
        }

        WindowsNativeEventFilter::lastMessageContext = ctx;
        const auto &contextCleaner = qScopeGuard([]() {
            WindowsNativeEventFilter::lastMessageContext = nullptr; //
        });

        // Since Qt does the necessary processing of the WM_NCCALCSIZE message, we need to
        // forward it right away and process it in our native event filter.
        if (message == WM_NCCALCSIZE) {
            WindowsNativeEventFilter::lastMessageContext = ctx;
            LRESULT result = ::CallWindowProcW(g_qtWindowProc, hWnd, message, wParam, lParam);
            WindowsNativeEventFilter::lastMessageContext = nullptr;
            return result;
            return ::CallWindowProcW(g_qtWindowProc, hWnd, message, wParam, lParam);
        }

        // Try hooked procedure and save result
        LRESULT result;
        if (ctx->windowProc(hWnd, message, wParam, lParam, &result)) {
            // https://github.com/stdware/qwindowkit/issues/45
            // Forward the event to user-defined native event filters, there may be some messages
            // that need to be processed by the user.
            std::ignore =
                forwardFilteredEvents(ctx->window(), hWnd, message, wParam, lParam, &result);
                forwardFilteredEvent(ctx->window(), hWnd, message, wParam, lParam, &result);
            return result;
        }

@@ -599,18 +647,10 @@
    }

    static inline void addManagedWindow(QWindow *window, HWND hWnd, Win32WindowContext *ctx) {
        const auto margins = [hWnd]() -> QMargins {
            const auto titleBarHeight = int(getTitleBarHeight(hWnd));
            if (isSystemBorderEnabled()) {
                return {0, -titleBarHeight, 0, 0};
            } else {
                const auto frameSize = int(getResizeBorderThickness(hWnd));
                return {-frameSize, -titleBarHeight, -frameSize, -frameSize};
            }
        }();

        // Inform Qt we want and have set custom margins
        setInternalWindowFrameMargins(window, margins);
        if (isSystemBorderEnabled()) {
            // Inform Qt we want and have set custom margins
            setInternalWindowFrameMargins(window, QMargins(0, -int(getTitleBarHeight(hWnd)), 0, 0));
        }

        // Store original window proc
        if (!g_qtWindowProc) {
@@ -669,12 +709,12 @@
                auto hWnd = reinterpret_cast<HWND>(m_windowId);
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
                const QPoint nativeGlobalPos =
                    QHighDpi::toNativeGlobalPosition(pos, m_windowHandle);
                    QHighDpi::toNativeGlobalPosition(pos, m_windowHandle.data());
#else
                const QPoint nativeGlobalPos = QHighDpi::toNativePixels(pos, m_windowHandle);
                const QPoint nativeGlobalPos = QHighDpi::toNativePixels(pos, m_windowHandle.data());
#endif
                showSystemMenu2(hWnd, qpoint2point(nativeGlobalPos), false,
                                m_delegate->isHostSizeFixed(m_host));
                std::ignore = showSystemMenu_sys(hWnd, qpoint2point(nativeGlobalPos), false,
                                                 isHostSizeFixed());
                return;
            }

@@ -793,6 +833,9 @@
                       : 0;
        }

        if (key == QStringLiteral("title-bar-height")) {
            return m_windowId ? int(getTitleBarHeight(reinterpret_cast<HWND>(m_windowId))) : 0;
        }
        return AbstractWindowContext::windowAttribute(key);
    }

@@ -800,6 +843,12 @@
        // Reset the context data
        mouseLeaveBlocked = false;
        lastHitTestResult = WindowPart::Outside;
        lastHitTestResultRaw = HTNOWHERE;

        if (!isSystemBorderEnabled()) {
            m_delegate->setWindowFlags(m_host, m_delegate->getWindowFlags(m_host) |
                                                   Qt::FramelessWindowHint);
        }

        // If the original window id is valid, remove all resources related
        if (oldWinId) {
@@ -1228,7 +1277,7 @@
                    POINT screenPoint{GET_X_LPARAM(dwScreenPos), GET_Y_LPARAM(dwScreenPos)};
                    ::ScreenToClient(hWnd, &screenPoint);
                    QPoint qtScenePos = QHighDpi::fromNativeLocalPosition(point2qpoint(screenPoint),
                                                                          m_windowHandle);
                                                                          m_windowHandle.data());
                    auto dummy = WindowAgentBase::Unknown;
                    if (isInSystemButtons(qtScenePos, &dummy)) {
                        // We must record whether the last WM_MOUSELEAVE was filtered, because if
@@ -1273,9 +1322,8 @@
    case WM_NCPOINTERUP:
#endif
            case WM_NCMOUSEHOVER: {
                const WindowPart currentWindowPart = lastHitTestResult;
                if (message == WM_NCMOUSEMOVE) {
                    if (currentWindowPart != WindowPart::ChromeButton) {
                    if (lastHitTestResult != WindowPart::ChromeButton) {
                        // https://github.com/qt/qtbase/blob/e26a87f1ecc40bc8c6aa5b889fce67410a57a702/src/widgets/kernel/qwidgetwindow.cpp#L472
                        // When the mouse press event arrives, QWidgetWindow will implicitly grab
                        // the top widget right under the mouse, and set `qt_button_down` to this
@@ -1334,14 +1382,50 @@
                    }
                }

                if (currentWindowPart == WindowPart::ChromeButton) {
                    emulateClientAreaMessage(hWnd, message, wParam, lParam);
                if (lastHitTestResult == WindowPart::ChromeButton) {
                    if (message == WM_NCMOUSEMOVE) {
                        // ### FIXME FIXME FIXME
                        // ### FIXME: Calling DefWindowProc() here is really dangerous, investigate
                        // how to avoid doing this.
                        // ### FIXME FIXME FIXME
                        *result = ::DefWindowProcW(hWnd, WM_NCMOUSEMOVE, wParam, lParam);
                        emulateClientAreaMessage(hWnd, message, wParam, lParam);
                        return true;
                    }

                    if (lastHitTestResultRaw == HTSYSMENU) {
                        switch (message) {
                            case WM_NCLBUTTONDOWN:
                                if (iconButtonClickLevel == 0) {
                                    // A message of WM_SYSCOMMAND with SC_MOUSEMENU will be sent by
                                    // Windows, and the current control flow will be blocked by the
                                    // menu while Windows will create and execute a new event loop
                                    // until the menu returns
                                    iconButtonClickTime = ::GetTickCount64();
                                    *result = ::DefWindowProcW(hWnd, message, wParam, lParam);
                                    iconButtonClickTime = 0;
                                    if (iconButtonClickLevel & IconButtonTriggersClose) {
                                        ::PostMessageW(hWnd, WM_SYSCOMMAND, SC_CLOSE, 0);
                                    }
                                    if (iconButtonClickLevel & IconButtonDoubleClicked) {
                                        iconButtonClickLevel = 0;
                                    }
                                    // Otherwise, no need to reset `iconButtonClickLevel` if not to
                                    // close, if it has value, there must be another incoming
                                    // WM_NCLBUTTONDOWN
                                } else {
                                    iconButtonClickLevel = 0;
                                }
                                break;
                            case WM_NCLBUTTONDBLCLK:
                                // A message of WM_SYSCOMMAND with SC_CLOSE will be sent by Windows
                                *result = ::DefWindowProcW(hWnd, message, wParam, lParam);
                                break;
                            default:
                                *result = FALSE;
                                emulateClientAreaMessage(hWnd, message, wParam, lParam);
                                break;
                        }
                    } else {
                        // According to MSDN, we should return non-zero for X button messages to
                        // indicate we have handled these messages (due to historical reasons), for
@@ -1350,6 +1434,7 @@
                            (((message >= WM_NCXBUTTONDOWN) && (message <= WM_NCXBUTTONDBLCLK))
                                 ? TRUE
                                 : FALSE);
                        emulateClientAreaMessage(hWnd, message, wParam, lParam);
                    }
                    return true;
                }
@@ -1479,7 +1564,8 @@
                // color, our homemade top border can almost have exactly the same
                // appearance with the system's one.
                [[maybe_unused]] const auto &hitTestRecorder = qScopeGuard([this, result]() {
                    lastHitTestResult = getHitWindowPart(int(*result)); //
                    lastHitTestResultRaw = int(*result);
                    lastHitTestResult = getHitWindowPart(lastHitTestResultRaw);
                });

                POINT nativeGlobalPos{GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
@@ -1491,15 +1577,24 @@
                auto clientWidth = RECT_WIDTH(clientRect);
                auto clientHeight = RECT_HEIGHT(clientRect);

                QPoint qtScenePos =
                    QHighDpi::fromNativeLocalPosition(point2qpoint(nativeLocalPos), m_windowHandle);
                QPoint qtScenePos = QHighDpi::fromNativeLocalPosition(point2qpoint(nativeLocalPos),
                                                                      m_windowHandle.data());

                bool isFixedSize = m_delegate->isHostSizeFixed(m_host);
                bool isTitleBar = isInTitleBarDraggableArea(qtScenePos);
                int frameSize = getResizeBorderThickness(hWnd);

                bool isFixedWidth = isHostWidthFixed();
                bool isFixedHeight = isHostHeightFixed();
                bool isFixedSize = isHostSizeFixed();
                bool isInLeftBorder = nativeLocalPos.x <= frameSize;
                bool isInTopBorder = nativeLocalPos.y <= frameSize;
                bool isInRightBorder = nativeLocalPos.x > clientWidth - frameSize;
                bool isInBottomBorder = nativeLocalPos.y > clientHeight - frameSize;
                bool isInTitleBar = isInTitleBarDraggableArea(qtScenePos);
                WindowAgentBase::SystemButton sysButtonType = WindowAgentBase::Unknown;
                bool isInCaptionButtons = isInSystemButtons(qtScenePos, &sysButtonType);
                bool dontOverrideCursor = false; // ### TODO

                WindowAgentBase::SystemButton sysButtonType = WindowAgentBase::Unknown;
                if (!isFixedSize && isInSystemButtons(qtScenePos, &sysButtonType)) {
                if (isInCaptionButtons) {
                    // Firstly, we set the hit test result to a default value to be able to detect
                    // whether we have changed it or not afterwards.
                    *result = HTNOWHERE;
@@ -1509,29 +1604,41 @@
                    // window is not maximized/fullscreen/minimized, of course).
                    if (isWindowNoState(hWnd)) {
                        static constexpr const quint8 kBorderSize = 2;
                        bool isTop = (nativeLocalPos.y <= kBorderSize);
                        bool isTop = nativeLocalPos.y <= kBorderSize;
                        bool isLeft = nativeLocalPos.x <= kBorderSize;
                        bool isRight = (nativeLocalPos.x >= (clientWidth - kBorderSize));
                        bool isRight = nativeLocalPos.x > clientWidth - kBorderSize;
                        if (isTop || isLeft || isRight) {
                            if (dontOverrideCursor) {
                            if (isFixedSize || dontOverrideCursor) {
                                // The user doesn't want the window to be resized, so we tell
                                // Windows we are in the client area so that the controls beneath
                                // the mouse cursor can still be hovered or clicked.
                                *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                                *result = isInTitleBar ? HTCAPTION : HTCLIENT;
                            } else {
                                if (isTop) {
                                    if (isLeft) {
                                        *result = HTTOPLEFT;
                                        if (isFixedWidth) {
                                            *result = HTTOP;
                                        } else if (isFixedHeight) {
                                            *result = HTLEFT;
                                        } else {
                                            *result = HTTOPLEFT;
                                        }
                                    } else if (isRight) {
                                        *result = HTTOPRIGHT;
                                        if (isFixedWidth) {
                                            *result = HTTOP;
                                        } else if (isFixedHeight) {
                                            *result = HTRIGHT;
                                        } else {
                                            *result = HTTOPRIGHT;
                                        }
                                    } else {
                                        *result = HTTOP;
                                        *result = isFixedHeight ? HTBORDER : HTTOP;
                                    }
                                } else {
                                    if (isLeft) {
                                        *result = HTLEFT;
                                    if (isFixedWidth) {
                                        *result = HTBORDER;
                                    } else {
                                        *result = HTRIGHT;
                                        *result = isLeft ? HTLEFT : HTRIGHT;
                                    }
                                }
                            }
@@ -1573,10 +1680,8 @@
                // OK, we are not inside any chrome buttons, try to find out which part of the
                // window are we hitting.

                bool max = IsMaximized(hWnd);
                bool max = isMaximized(hWnd);
                bool full = isFullScreen(hWnd);
                int frameSize = getResizeBorderThickness(hWnd);
                bool isTop = (nativeLocalPos.y < frameSize);

                if (isSystemBorderEnabled()) {
                    // This will handle the left, right and bottom parts of the frame
@@ -1588,8 +1693,51 @@
                        // outside the window, that is, the three transparent window resize area.
                        // Returning HTCLIENT will confuse Windows, we can't put our controls there
                        // anyway.
                        *result = ((isFixedSize || dontOverrideCursor) ? HTBORDER
                                                                       : originalHitTestResult);
                        *result = HTNOWHERE; // Make sure we can know we don't set any value
                                             // explicitly later.
                        if (originalHitTestResult == HTCAPTION) {
                        } else if (isFixedSize || dontOverrideCursor) {
                            *result = HTBORDER;
                        } else if (isFixedWidth || isFixedHeight) {
                            if (originalHitTestResult == HTTOPLEFT) {
                                if (isFixedWidth) {
                                    *result = HTTOP;
                                } else {
                                    *result = HTLEFT;
                                }
                            } else if (originalHitTestResult == HTTOPRIGHT) {
                                if (isFixedWidth) {
                                    *result = HTTOP;
                                } else {
                                    *result = HTRIGHT;
                                }
                            } else if (originalHitTestResult == HTBOTTOMRIGHT) {
                                if (isFixedWidth) {
                                    *result = HTBOTTOM;
                                } else {
                                    *result = HTRIGHT;
                                }
                            } else if (originalHitTestResult == HTBOTTOMLEFT) {
                                if (isFixedWidth) {
                                    *result = HTBOTTOM;
                                } else {
                                    *result = HTLEFT;
                                }
                            } else if (originalHitTestResult == HTLEFT ||
                                       originalHitTestResult == HTRIGHT) {
                                if (isFixedWidth) {
                                    *result = HTBORDER;
                                }
                            } else if (originalHitTestResult == HTTOP ||
                                       originalHitTestResult == HTBOTTOM) {
                                if (isFixedHeight) {
                                    *result = HTBORDER;
                                }
                            }
                        }
                        if (*result == HTNOWHERE) {
                            *result = originalHitTestResult;
                        }
                        return true;
                    }
                    if (full) {
@@ -1597,7 +1745,7 @@
                        return true;
                    }
                    if (max) {
                        *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                        *result = isInTitleBar ? HTCAPTION : HTCLIENT;
                        return true;
                    }
                    // At this point, we know that the cursor is inside the client area,
@@ -1605,16 +1753,25 @@
                    // title bar or the drag bar. Apparently, it must be the drag bar or
                    // the little border at the top which the user can use to move or
                    // resize the window.
                    if (isTop) {
                    if (isInTopBorder) {
                        // Return HTCLIENT instead of HTBORDER here, because the mouse is
                        // inside our homemade title bar now, return HTCLIENT to let our
                        // title bar can still capture mouse events.
                        *result = ((isFixedSize || dontOverrideCursor)
                                       ? (isTitleBar ? HTCAPTION : HTCLIENT)
                                       : HTTOP);
                        *result = [&]() {
                            if (isFixedSize || isFixedHeight || dontOverrideCursor ||
                                (isFixedWidth && (isInLeftBorder || isInRightBorder))) {
                                if (isInTitleBar) {
                                    return HTCAPTION;
                                } else {
                                    return HTCLIENT;
                                }
                            } else {
                                return HTTOP;
                            }
                        }();
                        return true;
                    }
                    if (isTitleBar) {
                    if (isInTitleBar) {
                        *result = HTCAPTION;
                        return true;
                    }
@@ -1625,58 +1782,86 @@
                        *result = HTCLIENT;
                        return true;
                    }
                    if (max) {
                        *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                    if (max || isFixedSize || dontOverrideCursor) {
                        *result = isInTitleBar ? HTCAPTION : HTCLIENT;
                        return true;
                    }
                    if (!isFixedSize) {
                        const bool isBottom = (nativeLocalPos.y >= (clientHeight - frameSize));
                        // Make the border a little wider to let the user easy to resize on corners.
                        const auto scaleFactor = ((isTop || isBottom) ? qreal(2) : qreal(1));
                        const int scaledFrameSize = std::round(qreal(frameSize) * scaleFactor);
                        const bool isLeft = (nativeLocalPos.x < scaledFrameSize);
                        const bool isRight = (nativeLocalPos.x >= (clientWidth - scaledFrameSize));
                        if (dontOverrideCursor && (isTop || isBottom || isLeft || isRight)) {
                            // Return HTCLIENT instead of HTBORDER here, because the mouse is
                            // inside the window now, return HTCLIENT to let the controls
                            // inside our window can still capture mouse events.
                            *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                            return true;
                    if (isFixedWidth || isFixedHeight) {
                        if (isInLeftBorder && isInTopBorder) {
                            if (isFixedWidth) {
                                *result = HTTOP;
                            } else {
                                *result = HTLEFT;
                            }
                        } else if (isInRightBorder && isInTopBorder) {
                            if (isFixedWidth) {
                                *result = HTTOP;
                            } else {
                                *result = HTRIGHT;
                            }
                        } else if (isInRightBorder && isInBottomBorder) {
                            if (isFixedWidth) {
                                *result = HTBOTTOM;
                            } else {
                                *result = HTRIGHT;
                            }
                        } else if (isInLeftBorder && isInBottomBorder) {
                            if (isFixedWidth) {
                                *result = HTBOTTOM;
                            } else {
                                *result = HTLEFT;
                            }
                        } else if (isInLeftBorder || isInRightBorder) {
                            if (isFixedWidth) {
                                *result = HTCLIENT;
                            } else {
                                *result = isInLeftBorder ? HTLEFT : HTRIGHT;
                            }
                        } else if (isInTopBorder || isInBottomBorder) {
                            if (isFixedHeight) {
                                *result = HTCLIENT;
                            } else {
                                *result = isInTopBorder ? HTTOP : HTBOTTOM;
                            }
                        } else {
                            *result = HTCLIENT;
                        }
                        if (isTop) {
                            if (isLeft) {
                        return true;
                    } else {
                        if (isInTopBorder) {
                            if (isInLeftBorder) {
                                *result = HTTOPLEFT;
                                return true;
                            }
                            if (isRight) {
                            if (isInRightBorder) {
                                *result = HTTOPRIGHT;
                                return true;
                            }
                            *result = HTTOP;
                            return true;
                        }
                        if (isBottom) {
                            if (isLeft) {
                        if (isInBottomBorder) {
                            if (isInLeftBorder) {
                                *result = HTBOTTOMLEFT;
                                return true;
                            }
                            if (isRight) {
                            if (isInRightBorder) {
                                *result = HTBOTTOMRIGHT;
                                return true;
                            }
                            *result = HTBOTTOM;
                            return true;
                        }
                        if (isLeft) {
                        if (isInLeftBorder) {
                            *result = HTLEFT;
                            return true;
                        }
                        if (isRight) {
                        if (isInRightBorder) {
                            *result = HTRIGHT;
                            return true;
                        }
                    }
                    if (isTitleBar) {
                    if (isInTitleBar) {
                        *result = HTCAPTION;
                        return true;
                    }
@@ -1869,9 +2054,9 @@
            // that's also how most applications customize their title bars on Windows. It's
            // totally OK but since we want to preserve as much original frame as possible,
            // we can't use that solution.
            const LRESULT hitTestResult = ::DefWindowProcW(hWnd, WM_NCCALCSIZE, wParam, lParam);
            if ((hitTestResult != HTERROR) && (hitTestResult != HTNOWHERE)) {
                *result = hitTestResult;
            const LRESULT originalResult = ::DefWindowProcW(hWnd, WM_NCCALCSIZE, wParam, lParam);
            if (originalResult != 0) {
                *result = originalResult;
                return true;
            }
            // Re-apply the original top from before the size of the default frame was
@@ -1885,7 +2070,7 @@
            clientRect->top = originalTop;
        }

        const bool max = IsMaximized(hWnd);
        const bool max = isMaximized(hWnd);
        const bool full = isFullScreen(hWnd);
        // We don't need this correction when we're fullscreen. We will
        // have the WS_POPUP size, so we don't have to worry about
@@ -1990,7 +2175,10 @@
        // of the upper-left non-client area. It's confirmed that this issue exists
        // from Windows 7 to Windows 10. Not tested on Windows 11 yet. Don't know
        // whether it exists on Windows XP to Windows Vista or not.
        *result = wParam ? WVR_REDRAW : FALSE;

        // https://github.com/chromium/chromium/blob/5d297da3cf2a642e9ace2b23fed097370bc70814/ui/views/win/hwnd_message_handler.cc#L2330
        // Do not return WVR_REDRAW otherwise child HWNDs will be mispositioned.
        *result = FALSE;
        return true;
    }

@@ -2000,7 +2188,7 @@
            return {GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
        };
        const auto getNativeGlobalPosFromKeyboard = [hWnd]() -> POINT {
            const bool maxOrFull = IsMaximized(hWnd) || isFullScreen(hWnd);
            const bool maxOrFull = isMaximized(hWnd) || isFullScreen(hWnd);
            const quint32 frameSize = getResizeBorderThickness(hWnd);
            const quint32 horizontalOffset =
                ((maxOrFull || !isSystemBorderEnabled()) ? 0 : frameSize);
@@ -2028,12 +2216,16 @@
        bool shouldShowSystemMenu = false;
        bool broughtByKeyboard = false;
        POINT nativeGlobalPos{};

        switch (message) {
            case WM_RBUTTONUP: {
                const POINT nativeLocalPos = getNativePosFromMouse();
                const QPoint qtScenePos =
                    QHighDpi::fromNativeLocalPosition(point2qpoint(nativeLocalPos), m_windowHandle);
                if (isInTitleBarDraggableArea(qtScenePos)) {
                const QPoint qtScenePos = QHighDpi::fromNativeLocalPosition(
                    point2qpoint(nativeLocalPos), m_windowHandle.data());
                WindowAgentBase::SystemButton sysButtonType = WindowAgentBase::Unknown;
                if (isInTitleBarDraggableArea(qtScenePos) ||
                    (isInSystemButtons(qtScenePos, &sysButtonType) &&
                     sysButtonType == WindowAgentBase::WindowIcon)) {
                    shouldShowSystemMenu = true;
                    nativeGlobalPos = nativeLocalPos;
                    ::ClientToScreen(hWnd, &nativeGlobalPos);
@@ -2049,10 +2241,20 @@
            }
            case WM_SYSCOMMAND: {
                const WPARAM filteredWParam = (wParam & 0xFFF0);
                if ((filteredWParam == SC_KEYMENU) && (lParam == VK_SPACE)) {
                    shouldShowSystemMenu = true;
                    broughtByKeyboard = true;
                    nativeGlobalPos = getNativeGlobalPosFromKeyboard();
                switch (filteredWParam) {
                    case SC_MOUSEMENU:
                        shouldShowSystemMenu = true;
                        nativeGlobalPos = getNativeGlobalPosFromKeyboard();
                        break;
                    case SC_KEYMENU:
                        if (lParam == VK_SPACE) {
                            shouldShowSystemMenu = true;
                            broughtByKeyboard = true;
                            nativeGlobalPos = getNativeGlobalPosFromKeyboard();
                        }
                        break;
                    default:
                        break;
                }
                break;
            }
@@ -2071,8 +2273,86 @@
                break;
        }
        if (shouldShowSystemMenu) {
            showSystemMenu2(hWnd, nativeGlobalPos, broughtByKeyboard,
                            m_delegate->isHostSizeFixed(m_host));
            static HHOOK mouseHook = nullptr;
            static std::optional<POINT> mouseClickPos;
            static bool mouseDoubleClicked = false;
            bool mouseHookedLocal = false;

            // The menu is triggered by a click on icon button
            if (iconButtonClickTime > 0) {
                POINT menuPos{0, static_cast<LONG>(getTitleBarHeight(hWnd))};
                if (const auto tb = titleBar()) {
                    auto titleBarHeight = qreal(m_delegate->mapGeometryToScene(tb).height());
                    titleBarHeight *= m_windowHandle->devicePixelRatio();
                    menuPos.y = qRound(titleBarHeight);
                }
                ::ClientToScreen(hWnd, &menuPos);
                nativeGlobalPos = menuPos;

                // Install mouse hook
                if (!mouseHook) {
                    mouseHook = ::SetWindowsHookExW(
                        WH_MOUSE,
                        [](int nCode, WPARAM wParam, LPARAM lParam) {
                            if (nCode >= 0) {
                                switch (wParam) {
                                    case WM_LBUTTONDBLCLK:
                                        mouseDoubleClicked = true;
                                        Q_FALLTHROUGH();

                                        // case WM_POINTERDOWN:

                                    case WM_LBUTTONDOWN: {
                                        auto pMouseStruct =
                                            reinterpret_cast<MOUSEHOOKSTRUCT *>(lParam);
                                        if (pMouseStruct) {
                                            mouseClickPos = pMouseStruct->pt;
                                        }
                                        break;
                                    }
                                    default:
                                        break;
                                }
                            }
                            return ::CallNextHookEx(nullptr, nCode, wParam, lParam);
                        },
                        nullptr, ::GetCurrentThreadId());
                    mouseHookedLocal = true;
                }
            }

            bool res =
                showSystemMenu_sys(hWnd, nativeGlobalPos, broughtByKeyboard, isHostSizeFixed());

            // Uninstall mouse hook and check if it's a double-click
            if (mouseHookedLocal) {
                ::UnhookWindowsHookEx(mouseHook);

                // Emulate the Windows icon button's behavior
                if (!res && mouseClickPos.has_value()) {
                    POINT nativeLocalPos = mouseClickPos.value();
                    ::ScreenToClient(hWnd, &nativeLocalPos);
                    QPoint qtScenePos = QHighDpi::fromNativeLocalPosition(
                        point2qpoint(nativeLocalPos), m_windowHandle.data());
                    WindowAgentBase::SystemButton sysButtonType = WindowAgentBase::Unknown;
                    if (isInSystemButtons(qtScenePos, &sysButtonType) &&
                        sysButtonType == WindowAgentBase::WindowIcon) {
                        iconButtonClickLevel |= IconButtonClicked;
                        if (::GetTickCount64() - iconButtonClickTime <= ::GetDoubleClickTime()) {
                            iconButtonClickLevel |= IconButtonTriggersClose;
                        }
                    }
                }

                if (mouseDoubleClicked) {
                    iconButtonClickLevel |= IconButtonDoubleClicked;
                }

                mouseHook = nullptr;
                mouseClickPos.reset();
                mouseDoubleClicked = false;
            }

            // QPA's internal code will handle system menu events separately, and its
            // behavior is not what we would want to see because it doesn't know our
            // window doesn't have any window frame now, so return early here to avoid