sola/qwindowkit.git

			@@ -62,6 +62,82 @@
			_DWMWA_MICA_EFFECT = 1029
			};

			// Types used with DWMWA_SYSTEMBACKDROP_TYPE
			enum _DWM_SYSTEMBACKDROP_TYPE {
			_DWMSBT_AUTO, // [Default] Let DWM automatically decide the system-drawn backdrop for this window.
			_DWMSBT_NONE, // [Disable] Do not draw any system backdrop.
			_DWMSBT_MAINWINDOW, // [Mica] Draw the backdrop material effect corresponding to a long-lived window.
			_DWMSBT_TRANSIENTWINDOW, // [Acrylic] Draw the backdrop material effect corresponding to a transient window.
			_DWMSBT_TABBEDWINDOW, // [Mica Alt] Draw the backdrop material effect corresponding to a window with a tabbed title bar.
			};

			enum WINDOWCOMPOSITIONATTRIB {
			WCA_UNDEFINED = 0,
			WCA_NCRENDERING_ENABLED = 1,
			WCA_NCRENDERING_POLICY = 2,
			WCA_TRANSITIONS_FORCEDISABLED = 3,
			WCA_ALLOW_NCPAINT = 4,
			WCA_CAPTION_BUTTON_BOUNDS = 5,
			WCA_NONCLIENT_RTL_LAYOUT = 6,
			WCA_FORCE_ICONIC_REPRESENTATION = 7,
			WCA_EXTENDED_FRAME_BOUNDS = 8,
			WCA_HAS_ICONIC_BITMAP = 9,
			WCA_THEME_ATTRIBUTES = 10,
			WCA_NCRENDERING_EXILED = 11,
			WCA_NCADORNMENTINFO = 12,
			WCA_EXCLUDED_FROM_LIVEPREVIEW = 13,
			WCA_VIDEO_OVERLAY_ACTIVE = 14,
			WCA_FORCE_ACTIVEWINDOW_APPEARANCE = 15,
			WCA_DISALLOW_PEEK = 16,
			WCA_CLOAK = 17,
			WCA_CLOAKED = 18,
			WCA_ACCENT_POLICY = 19,
			WCA_FREEZE_REPRESENTATION = 20,
			WCA_EVER_UNCLOAKED = 21,
			WCA_VISUAL_OWNER = 22,
			WCA_HOLOGRAPHIC = 23,
			WCA_EXCLUDED_FROM_DDA = 24,
			WCA_PASSIVEUPDATEMODE = 25,
			WCA_USEDARKMODECOLORS = 26,
			WCA_CORNER_STYLE = 27,
			WCA_PART_COLOR = 28,
			WCA_DISABLE_MOVESIZE_FEEDBACK = 29,
			WCA_LAST = 30
			};

			enum ACCENT_STATE {
			ACCENT_DISABLED = 0,
			ACCENT_ENABLE_GRADIENT = 1,
			ACCENT_ENABLE_TRANSPARENTGRADIENT = 2,
			ACCENT_ENABLE_BLURBEHIND = 3, // Traditional DWM blur
			ACCENT_ENABLE_ACRYLICBLURBEHIND = 4, // RS4 1803
			ACCENT_ENABLE_HOST_BACKDROP = 5, // RS5 1809
			ACCENT_INVALID_STATE = 6 // Using this value will remove the window background
			};

			enum ACCENT_FLAG {
			ACCENT_NONE = 0,
			ACCENT_ENABLE_ACRYLIC = 1,
			ACCENT_ENABLE_ACRYLIC_WITH_LUMINOSITY = 482
			};

			struct ACCENT_POLICY {
			DWORD dwAccentState;
			DWORD dwAccentFlags;
			DWORD dwGradientColor; // #AABBGGRR
			DWORD dwAnimationId;
			};
			using PACCENT_POLICY = ACCENT_POLICY *;

			struct WINDOWCOMPOSITIONATTRIBDATA {
			WINDOWCOMPOSITIONATTRIB Attrib;
			PVOID pvData;
			SIZE_T cbData;
			};
			using PWINDOWCOMPOSITIONATTRIBDATA = WINDOWCOMPOSITIONATTRIBDATA *;

			using SetWindowCompositionAttributePtr = BOOL(WINAPI *)(HWND, PWINDOWCOMPOSITIONATTRIBDATA);

			// The thickness of an auto-hide taskbar in pixels.
			static constexpr const quint8 kAutoHideTaskBarThickness = 2;

			@@ -105,6 +181,7 @@
			DYNAMIC_API_DECLARE(DwmGetCompositionTimingInfo);
			DYNAMIC_API_DECLARE(DwmGetWindowAttribute);
			DYNAMIC_API_DECLARE(DwmSetWindowAttribute);
			DYNAMIC_API_DECLARE(DwmExtendFrameIntoClientArea);
			DYNAMIC_API_DECLARE(GetDpiForWindow);
			DYNAMIC_API_DECLARE(GetSystemMetricsForDpi);
			DYNAMIC_API_DECLARE(GetDpiForMonitor);
			@@ -114,6 +191,8 @@

			#undef DYNAMIC_API_DECLARE

			SetWindowCompositionAttributePtr pSetWindowCompositionAttribute = nullptr;

			private:
			DynamicApis() {
			#define DYNAMIC_API_RESOLVE(DLL, NAME) \
			@@ -122,6 +201,7 @@
			QSystemLibrary user32(QStringLiteral("user32"));
			DYNAMIC_API_RESOLVE(user32, GetDpiForWindow);
			DYNAMIC_API_RESOLVE(user32, GetSystemMetricsForDpi);
			DYNAMIC_API_RESOLVE(user32, SetWindowCompositionAttribute);

			QSystemLibrary shcore(QStringLiteral("shcore"));
			DYNAMIC_API_RESOLVE(shcore, GetDpiForMonitor);
			@@ -132,6 +212,7 @@
			DYNAMIC_API_RESOLVE(dwmapi, DwmGetCompositionTimingInfo);
			DYNAMIC_API_RESOLVE(dwmapi, DwmGetWindowAttribute);
			DYNAMIC_API_RESOLVE(dwmapi, DwmSetWindowAttribute);
			DYNAMIC_API_RESOLVE(dwmapi, DwmExtendFrameIntoClientArea);

			QSystemLibrary winmm(QStringLiteral("winmm"));
			DYNAMIC_API_RESOLVE(winmm, timeGetDevCaps);
			@@ -243,6 +324,11 @@

			static inline bool isWin11OrGreater() {
			static const bool result = IsWindows11OrGreater_Real();
			return result;
			}

			static inline bool isWin1122H2OrGreater() {
			static const bool result = IsWindows1122H2OrGreater_Real();
			return result;
			}

			@@ -379,16 +465,7 @@
			getSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi);
			}

			static void updateInternalWindowFrameMargins(HWND hwnd, QWindow *window) {
			const auto margins = [hwnd]() -> QMargins {
			const auto titleBarHeight = int(getTitleBarHeight(hwnd));
			if (isWin10OrGreater()) {
			return {0, -titleBarHeight, 0, 0};
			} else {
			const auto frameSize = int(getResizeBorderThickness(hwnd));
			return {-frameSize, -titleBarHeight, -frameSize, -frameSize};
			}
			}();
			static void setInternalWindowFrameMargins(QWindow *window, const QMargins &margins) {
			const QVariant marginsVar = QVariant::fromValue(margins);
			window->setProperty("_q_windowsCustomMargins", marginsVar);
			#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
			@@ -414,16 +491,83 @@
			monitorInfo.cbSize = sizeof(monitorInfo);
			::GetMonitorInfoW(monitor, &monitorInfo);
			return monitorInfo;
			};
			}

			static inline void moveToDesktopCenter(HWND hwnd) {
			const auto monitorInfo = getMonitorForWindow(hwnd);
			static inline void moveWindowToDesktopCenter(HWND hwnd) {
			MONITORINFOEXW monitorInfo = getMonitorForWindow(hwnd);
			RECT windowRect{};
			::GetWindowRect(hwnd, &windowRect);
			const auto newX = monitorInfo.rcMonitor.left + (RECT_WIDTH(monitorInfo.rcMonitor) - RECT_WIDTH(windowRect)) / 2;
			const auto newY = monitorInfo.rcMonitor.top + (RECT_HEIGHT(monitorInfo.rcMonitor) - RECT_HEIGHT(windowRect)) / 2;
			const auto newX = monitorInfo.rcMonitor.left +
			(RECT_WIDTH(monitorInfo.rcMonitor) - RECT_WIDTH(windowRect)) / 2;
			const auto newY = monitorInfo.rcMonitor.top +
			(RECT_HEIGHT(monitorInfo.rcMonitor) - RECT_HEIGHT(windowRect)) / 2;
			::SetWindowPos(hwnd, nullptr, newX, newY, 0, 0,
			SWP_NOACTIVATE \| SWP_NOSIZE \| SWP_NOZORDER \| SWP_NOOWNERZORDER);
			}

			static inline void moveWindowToMonitor(HWND hwnd, const MONITORINFOEXW &activeMonitor) {
			RECT currentMonitorRect = getMonitorForWindow(hwnd).rcMonitor;
			RECT activeMonitorRect = activeMonitor.rcMonitor;
			// We are in the same monitor, nothing to adjust here.
			if (currentMonitorRect == activeMonitorRect) {
			return;
			}
			RECT currentWindowRect{};
			::GetWindowRect(hwnd, &currentWindowRect);
			auto newWindowX =
			activeMonitorRect.left + (currentWindowRect.left - currentMonitorRect.left);
			auto newWindowY = activeMonitorRect.top + (currentWindowRect.top - currentMonitorRect.top);
			::SetWindowPos(hwnd, nullptr, newWindowX, newWindowY, RECT_WIDTH(currentWindowRect),
			RECT_HEIGHT(currentWindowRect),
			SWP_NOACTIVATE \| SWP_NOSIZE \| SWP_NOZORDER \| SWP_NOOWNERZORDER);
			}

			static inline void bringWindowToFront(HWND hwnd) {
			HWND oldForegroundWindow = ::GetForegroundWindow();
			if (!oldForegroundWindow) {
			// The foreground window can be NULL, it's not an API error.
			return;
			}
			MONITORINFOEXW activeMonitor = getMonitorForWindow(oldForegroundWindow);
			// We need to show the window first, otherwise we won't be able to bring it to front.
			if (!::IsWindowVisible(hwnd)) {
			::ShowWindow(hwnd, SW_SHOW);
			}
			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.
			moveWindowToMonitor(hwnd, activeMonitor);
			// When the window is restored, it will always become the foreground window.
			// So return early here, we don't need the following code to bring it to front.
			return;
			}
			// OK, our window is not minimized, so now we will try to bring it to front manually.
			// First try to send a message to the current foreground window to check whether
			// it is currently hanging or not.
			if (!::SendMessageTimeoutW(oldForegroundWindow, WM_NULL, 0, 0,
			SMTO_BLOCK \| SMTO_ABORTIFHUNG \| SMTO_NOTIMEOUTIFNOTHUNG, 1000,
			nullptr)) {
			// The foreground window hangs, can't activate current window.
			return;
			}
			DWORD windowThreadProcessId = ::GetWindowThreadProcessId(oldForegroundWindow, nullptr);
			DWORD currentThreadId = ::GetCurrentThreadId();
			// We won't be able to change a window's Z order if it's not our own window,
			// so we use this small technique to pretend the foreground window is ours.
			::AttachThreadInput(windowThreadProcessId, currentThreadId, TRUE);

			[[maybe_unused]] const auto &cleaner =
			qScopeGuard([windowThreadProcessId, currentThreadId]() {
			::AttachThreadInput(windowThreadProcessId, currentThreadId, FALSE); //
			});

			::BringWindowToTop(hwnd);
			// Activate the window too. This will force us to the virtual desktop this
			// window is on, if it's on another virtual desktop.
			::SetActiveWindow(hwnd);
			// Throw us on the active monitor.
			moveWindowToMonitor(hwnd, activeMonitor);
			}

			static inline bool isFullScreen(HWND hwnd) {
			@@ -762,18 +906,52 @@
			return ::CallWindowProcW(g_qtWindowProc, hWnd, message, wParam, lParam);
			}

			static inline void addManagedWindow(QWindow window, HWND hWnd, Win32WindowContext ctx) {
			const auto margins = [hWnd]() -> QMargins {
			const auto titleBarHeight = int(getTitleBarHeight(hWnd));
			if (isWin10OrGreater()) {
			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);

			// Store original window proc
			if (!g_qtWindowProc) {
			g_qtWindowProc = reinterpret_cast<WNDPROC>(::GetWindowLongPtrW(hWnd, GWLP_WNDPROC));
			}

			// Hook window proc
			::SetWindowLongPtrW(hWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(QWKHookedWndProc));

			// Install global native event filter
			WindowsNativeEventFilter::install();

			// Save window handle mapping
			g_wndProcHash->insert(hWnd, ctx);
			}

			static inline void removeManagedWindow(HWND hWnd) {
			// Remove window handle mapping
			if (!g_wndProcHash->remove(hWnd))
			return;

			// Remove event filter if the all windows has been destroyed
			if (g_wndProcHash->empty()) {
			WindowsNativeEventFilter::uninstall();
			}
			}

			Win32WindowContext::Win32WindowContext() : AbstractWindowContext() {
			}

			Win32WindowContext::~Win32WindowContext() {
			// Remove window handle mapping
			if (auto hWnd = reinterpret_cast<HWND>(windowId); hWnd) {
			g_wndProcHash->remove(hWnd);

			// Remove event filter if the all windows has been destroyed
			if (g_wndProcHash->empty()) {
			WindowsNativeEventFilter::uninstall();
			}
			if (windowId) {
			removeManagedWindow(reinterpret_cast<HWND>(windowId));
			}
			}

			@@ -784,21 +962,141 @@
			void Win32WindowContext::virtual_hook(int id, void *data) {
			switch (id) {
			case CentralizeHook: {
			const auto hwnd = reinterpret_cast<HWND>(m_windowHandle->winId());
			moveToDesktopCenter(hwnd);
			if (!windowId)
			return;
			const auto hwnd = reinterpret_cast<HWND>(windowId);
			moveWindowToDesktopCenter(hwnd);
			return;
			}

			case RaiseWindowHook: {
			if (!windowId)
			return;
			const auto hwnd = reinterpret_cast<HWND>(windowId);
			bringWindowToFront(hwnd);
			return;
			}

			case ShowSystemMenuHook: {
			if (!windowId)
			return;
			const auto &pos = static_cast<const QPoint >(data);
			auto hWnd = reinterpret_cast<HWND>(m_windowHandle->winId());
			auto hWnd = reinterpret_cast<HWND>(windowId);
			#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
			const QPoint nativeGlobalPos = QHighDpi::toNativeGlobalPosition(pos, m_windowHandle);
			const QPoint nativeGlobalPos =
			QHighDpi::toNativeGlobalPosition(pos, m_windowHandle);
			#else
			const QPoint nativeGlobalPos = QHighDpi::toNativePixels(pos, m_windowHandle);
			#endif
			showSystemMenu2(hWnd, qpoint2point(nativeGlobalPos), false,
			m_delegate->isHostSizeFixed(m_host));
			return;
			}

			case WindowAttributeChangedHook: {
			auto args = static_cast<void **>(data);
			const auto &key = static_cast<const QString >(args[0]);
			const auto &newVar = static_cast<const QVariant >(args[1]);
			const auto &oldVar = static_cast<const QVariant >(args[2]);

			if (!windowId)
			return;
			const auto hwnd = reinterpret_cast<HWND>(windowId);

			const DynamicApis &apis = DynamicApis::instance();

			if (key == QStringLiteral("frame-shadow")) {
			if (newVar.toBool()) {
			// TODO: set off
			} else {
			// TODO: set on
			}
			} else if (key == QStringLiteral("mica")) {
			if (!isWin11OrGreater()) {
			return;
			}
			if (newVar.toBool()) {
			// We need to extend the window frame into the whole client area to be able
			// to see the blurred window background.
			static constexpr const MARGINS margins = {-1, -1, -1, -1};
			apis.pDwmExtendFrameIntoClientArea(hwnd, &margins);
			if (isWin1122H2OrGreater()) {
			// Use official DWM API to enable Mica, available since Windows 11 22H2 (10.0.22621).
			const _DWM_SYSTEMBACKDROP_TYPE backdropType = _DWMSBT_MAINWINDOW;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_SYSTEMBACKDROP_TYPE, &backdropType, sizeof(backdropType));
			} else {
			// Use undocumented DWM API to enable Mica, available since Windows 11 (10.0.22000).
			const BOOL enable = TRUE;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_MICA_EFFECT, &enable, sizeof(enable));
			}
			} else {
			if (isWin1122H2OrGreater()) {
			const _DWM_SYSTEMBACKDROP_TYPE backdropType = _DWMSBT_AUTO;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_SYSTEMBACKDROP_TYPE, &backdropType, sizeof(backdropType));
			} else {
			const BOOL enable = FALSE;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_MICA_EFFECT, &enable, sizeof(enable));
			}
			static constexpr const MARGINS margins = {0, 0, 0, 0};
			apis.pDwmExtendFrameIntoClientArea(hwnd, &margins);
			}
			} else if (key == QStringLiteral("mica-alt")) {
			if (!isWin1122H2OrGreater()) {
			return;
			}
			if (newVar.toBool()) {
			// We need to extend the window frame into the whole client area to be able
			// to see the blurred window background.
			static constexpr const MARGINS margins = {-1, -1, -1, -1};
			apis.pDwmExtendFrameIntoClientArea(hwnd, &margins);
			// Use official DWM API to enable Mica Alt, available since Windows 11 22H2 (10.0.22621).
			const _DWM_SYSTEMBACKDROP_TYPE backdropType = _DWMSBT_TABBEDWINDOW;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_SYSTEMBACKDROP_TYPE, &backdropType, sizeof(backdropType));
			} else {
			const _DWM_SYSTEMBACKDROP_TYPE backdropType = _DWMSBT_AUTO;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_SYSTEMBACKDROP_TYPE, &backdropType, sizeof(backdropType));
			static constexpr const MARGINS margins = {0, 0, 0, 0};
			apis.pDwmExtendFrameIntoClientArea(hwnd, &margins);
			}
			} else if (key == QStringLiteral("acrylic-material")) {
			if (newVar.toBool()) {
			// We need to extend the window frame into the whole client area to be able
			// to see the blurred window background.
			static constexpr const MARGINS margins = {-1, -1, -1, -1};
			apis.pDwmExtendFrameIntoClientArea(hwnd, &margins);
			if (isWin11OrGreater()) {
			const _DWM_SYSTEMBACKDROP_TYPE backdropType = _DWMSBT_TRANSIENTWINDOW;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_SYSTEMBACKDROP_TYPE, &backdropType, sizeof(backdropType));
			} else {
			ACCENT_POLICY policy{};
			policy.dwAccentState = ACCENT_ENABLE_ACRYLICBLURBEHIND;
			policy.dwAccentFlags = ACCENT_ENABLE_ACRYLIC_WITH_LUMINOSITY;
			// This API expects the #AABBGGRR format.
			//policy.dwGradientColor = DWORD(qRgba(gradientColor.blue(), gradientColor.green(), gradientColor.red(), gradientColor.alpha()));
			WINDOWCOMPOSITIONATTRIBDATA wcad{};
			wcad.Attrib = WCA_ACCENT_POLICY;
			wcad.pvData = &policy;
			wcad.cbData = sizeof(policy);
			apis.pSetWindowCompositionAttribute(hwnd, &wcad);
			}
			} else {
			if (isWin11OrGreater()) {
			const _DWM_SYSTEMBACKDROP_TYPE backdropType = _DWMSBT_AUTO;
			apis.pDwmSetWindowAttribute(hwnd, _DWMWA_SYSTEMBACKDROP_TYPE, &backdropType, sizeof(backdropType));
			} else {
			ACCENT_POLICY policy{};
			policy.dwAccentState = ACCENT_DISABLED;
			policy.dwAccentFlags = ACCENT_NONE;
			WINDOWCOMPOSITIONATTRIBDATA wcad{};
			wcad.Attrib = WCA_ACCENT_POLICY;
			wcad.pvData = &policy;
			wcad.cbData = sizeof(policy);
			apis.pSetWindowCompositionAttribute(hwnd, &wcad);
			}
			static constexpr const MARGINS margins = {0, 0, 0, 0};
			apis.pDwmExtendFrameIntoClientArea(hwnd, &margins);
			}
			}
			return;
			}

			@@ -813,11 +1111,14 @@
			}

			case DrawWindows10BorderHook: {
			if (!windowId)
			return;

			auto args = static_cast<void **>(data);
			auto &painter = static_cast<QPainter >(args[0]);
			const auto &rect = static_cast<const QRect >(args[1]);
			const auto &region = static_cast<const QRegion >(args[2]);
			const auto hwnd = reinterpret_cast<HWND>(m_windowHandle->winId());
			const auto hwnd = reinterpret_cast<HWND>(windowId);

			QPen pen;
			pen.setWidth(getWindowFrameBorderThickness(hwnd) * 2);
			@@ -852,10 +1153,8 @@
			return;
			}

			default: {
			// unreachable
			default:
			break;
			}
			}
			AbstractWindowContext::virtual_hook(id, data);
			}
			@@ -868,39 +1167,36 @@
			return getWindowFrameBorderThickness(reinterpret_cast<HWND>(windowId));
			}

			bool Win32WindowContext::setupHost() {
			void Win32WindowContext::winIdChanged() {
			// If the original window id is valid, remove all resources related
			if (windowId) {
			removeManagedWindow(reinterpret_cast<HWND>(windowId));
			windowId = 0;
			}

			if (!m_windowHandle) {
			return;
			}

			// Install window hook
			auto winId = m_windowHandle->winId();
			auto hWnd = reinterpret_cast<HWND>(winId);

			#if QT_VERSION < QT_VERSION_CHECK(6, 5, 0)
			for (const auto attr : { _DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1, _DWMWA_USE_IMMERSIVE_DARK_MODE }) {
			for (const auto attr : {
			_DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1,
			_DWMWA_USE_IMMERSIVE_DARK_MODE,
			}) {
			const BOOL enable = TRUE;
			DynamicApis::instance().pDwmSetWindowAttribute(hWnd, attr, &enable, sizeof(enable));
			}
			#endif

			// Inform Qt we want and have set custom margins
			updateInternalWindowFrameMargins(hWnd, m_windowHandle);
			// Add managed window
			addManagedWindow(m_windowHandle, hWnd, this);

			// Store original window proc
			if (!g_qtWindowProc) {
			g_qtWindowProc = reinterpret_cast<WNDPROC>(::GetWindowLongPtrW(hWnd, GWLP_WNDPROC));
			}

			// Hook window proc
			::SetWindowLongPtrW(hWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(QWKHookedWndProc));

			// Install global native event filter
			WindowsNativeEventFilter::install();

			// Cache window ID
			// Cache win id
			windowId = winId;

			// Save window handle mapping
			g_wndProcHash->insert(hWnd, this);

			return true;
			}

			bool Win32WindowContext::windowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam,
			@@ -1161,6 +1457,53 @@
			const WindowPart currentWindowPart = lastHitTestResult;
			if (message == WM_NCMOUSEMOVE) {
			if (currentWindowPart != 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
			// widget. At this time, no other widgets will accept the mouse event until
			// QWidgetWindow receives the mouse release event, then set `qt_button_down`
			// to null.

			// Imagine the following situation, now the main window has a pop-up menu,
			// the focus is not on the main window, if we click outside the pop-up menu,
			// the menu will close, which seems to be completely fine. But if we close
			// the menu by clicking on the title bar draggable area, then other widgets
			// won't accept the mouse message afterwards.

			// Here's the reason.
			// When the mouse is placed in the draggable area of the title bar, there
			// are two situations.

			// 1. If the focus is on the main window, and the last result of
			// WM_NCHITTEST is HTCAPTION, the mouse click event in the title bar is
			// taken over by Windows and Qt does not receive the mouse click event.

			// 2. If the main window has a pop-up menu, it is completely different. When
			// the mouse is pressed on the title bar, Windows sends the WM_LBUTTONDOWN
			// message to the window plane of the pop-up menu, the menu is closed, but
			// Qt will continue to forward the event to the QWidget under the mouse, and
			// the event will be processed by QWidgetWindow, causing the title bar
			// widget to be implicitly grabbed. After the menu is closed, Windows
			// immediately sends WM_NCHITTEST, because the mouse is in the title bar
			// draggable area, the result is HTCAPTION, so when the mouse is released,
			// Windows sends WM_NCLBUTTONUP, which is a non-client message, and it
			// will be ignored by Qt. As a consequence, QWidgetWindow can't receive a
			// mouse release message in the client area, so the grab remains, and other
			// widgets cannot receive mouse events.

			// Since we didn't watch the menu window, we cannot capture any mouse
			// press events sent by Windows, so we cannot solve this problem by
			// recording mouse events. Fortunately, we found that the main window will
			// receive a WM_NCMOUSEMOVE message immediately after the menu is closed, so
			// we just manually send a mouse release event when this message arrives and
			// set qt_button_down to null. Don't worry, when receiving WM_NCMOUSEMOVE,
			// there shouldn't be any control in the state of being grabbed.

			// In the native window, although QWidgetWindow handles the forwarded mouse
			// press event when the menu is closed, since the native title bar is not a
			// QWidget, no widget will be grabbed, and `qt_button_down` remains empty,
			// the above problems would not arise.

			m_delegate->resetQtGrabbedControl(m_host);
			if (mouseLeaveBlocked) {
			emulateClientAreaMessage(hWnd, message, wParam, lParam,
			@@ -1223,6 +1566,8 @@
			// window from client area, which means we will get previous window part as
			// HTCLIENT if the mouse leaves window from client area and enters window
			// from non-client area, but it has no bad effect.

			// Why do we need to call this function here?
			m_delegate->resetQtGrabbedControl(m_host);
			}
			}
			@@ -1245,7 +1590,7 @@
			// function.
			if (wParam && !lParam) {
			centered = true;
			moveToDesktopCenter(hWnd);
			moveWindowToDesktopCenter(hWnd);
			}
			}
			break;
			@@ -1332,7 +1677,6 @@
			// Terminal does, however, later I found that if we choose a proper
			// 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)); //
			});
			@@ -1455,7 +1799,7 @@
			*result = (isTitleBar ? HTCAPTION : HTCLIENT);
			return true;
			}
			// At this point, we know that the cursor is inside the client area
			// At this point, we know that the cursor is inside the client area,
			// so it has to be either the little border at the top of our custom
			// 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
			@@ -1548,8 +1892,10 @@
			// the client area as a whole will shift to the left, which looks very abnormal if
			// we don't repaint it. This exception disappears if we add SWP_NOCOPYBITS flag.
			// But I don't know what caused the problem, or why this would solve it.
			static constexpr const auto kBadWindowPosFlag =
			SWP_NOSIZE \| SWP_NOMOVE \| SWP_NOZORDER \| SWP_NOACTIVATE \| SWP_FRAMECHANGED;
			const auto windowPos = reinterpret_cast<LPWINDOWPOS>(lParam);
			if (windowPos->flags == 0x37) {
			if (windowPos->flags == kBadWindowPosFlag) {
			windowPos->flags \|= SWP_NOCOPYBITS;
			}
			break;