diff --git a/Telegram/Resources/langs/lang.strings b/Telegram/Resources/langs/lang.strings
index 7787db0a05..ca96cce888 100644
--- a/Telegram/Resources/langs/lang.strings
+++ b/Telegram/Resources/langs/lang.strings
@@ -338,6 +338,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_settings_update_fail" = "Update check failed :(";
 "lng_settings_workmode_tray" = "Show tray icon";
 "lng_settings_workmode_window" = "Show taskbar icon";
+"lng_settings_native_frame" = "Use system window frame";
 "lng_settings_auto_start" = "Launch Telegram when system starts";
 "lng_settings_start_min" = "Launch minimized";
 "lng_settings_add_sendto" = "Place Telegram in \"Send to\" menu";
diff --git a/Telegram/SourceFiles/core/core_settings.cpp b/Telegram/SourceFiles/core/core_settings.cpp
index 23c5d0eaf7..1988fec580 100644
--- a/Telegram/SourceFiles/core/core_settings.cpp
+++ b/Telegram/SourceFiles/core/core_settings.cpp
@@ -105,7 +105,8 @@ QByteArray Settings::serialize() const {
 				1000000))
 			<< qint32(_thirdColumnWidth.current())
 			<< qint32(_thirdSectionExtendedBy)
-			<< qint32(_notifyFromAll ? 1 : 0);
+			<< qint32(_notifyFromAll ? 1 : 0)
+			<< qint32(_nativeWindowFrame.current() ? 1 : 0);
 	}
 	return result;
 }
@@ -169,6 +170,7 @@ void Settings::addFromSerialized(const QByteArray &serialized) {
 	qint32 thirdColumnWidth = _thirdColumnWidth.current();
 	qint32 thirdSectionExtendedBy = _thirdSectionExtendedBy;
 	qint32 notifyFromAll = _notifyFromAll ? 1 : 0;
+	qint32 nativeWindowFrame = _nativeWindowFrame.current() ? 1 : 0;
 
 	stream >> themesAccentColors;
 	if (!stream.atEnd()) {
@@ -243,6 +245,9 @@ void Settings::addFromSerialized(const QByteArray &serialized) {
 			>> notifyFromAll;
 		dialogsWidthRatio = snap(dialogsWidthRatioInt / 1000000., 0., 1.);
 	}
+	if (!stream.atEnd()) {
+		stream >> nativeWindowFrame;
+	}
 	if (stream.status() != QDataStream::Ok) {
 		LOG(("App Error: "
 			"Bad data for Core::Settings::constructFromSerialized()"));
@@ -335,6 +340,7 @@ void Settings::addFromSerialized(const QByteArray &serialized) {
 		_tabbedSelectorSectionEnabled = false;
 	}
 	_notifyFromAll = (notifyFromAll == 1);
+	_nativeWindowFrame = (nativeWindowFrame == 1);
 }
 
 bool Settings::chatWide() const {
diff --git a/Telegram/SourceFiles/core/core_settings.h b/Telegram/SourceFiles/core/core_settings.h
index b8eae179e2..144b4977c4 100644
--- a/Telegram/SourceFiles/core/core_settings.h
+++ b/Telegram/SourceFiles/core/core_settings.h
@@ -407,6 +407,15 @@ public:
 	[[nodiscard]] bool notifyFromAll() const {
 		return _notifyFromAll;
 	}
+	void setNativeWindowFrame(bool value) {
+		_nativeWindowFrame = value;
+	}
+	[[nodiscard]] bool nativeWindowFrame() const {
+		return _nativeWindowFrame.current();
+	}
+	[[nodiscard]] rpl::producer<bool> nativeWindowFrameChanges() const {
+		return _nativeWindowFrame.changes();
+	}
 
 	[[nodiscard]] static bool ThirdColumnByDefault();
 	[[nodiscard]] float64 DefaultDialogsWidthRatio();
@@ -474,6 +483,7 @@ private:
 	rpl::variable<float64> _dialogsWidthRatio; // per-window
 	rpl::variable<int> _thirdColumnWidth = kDefaultThirdColumnWidth; // p-w
 	bool _notifyFromAll = true;
+	rpl::variable<bool> _nativeWindowFrame = false;
 
 	bool _tabbedReplacedWithInfo = false; // per-window
 	rpl::event_stream<bool> _tabbedReplacedWithInfoValue; // per-window
diff --git a/Telegram/SourceFiles/mainwidget.cpp b/Telegram/SourceFiles/mainwidget.cpp
index a6f20da2f4..efe872c44d 100644
--- a/Telegram/SourceFiles/mainwidget.cpp
+++ b/Telegram/SourceFiles/mainwidget.cpp
@@ -2177,13 +2177,19 @@ void MainWidget::updateControlsGeometry() {
 		auto mainSectionWidth = width() - dialogsWidth - thirdSectionWidth;
 
 		_dialogs->setGeometryWithTopMoved({ 0, 0, dialogsWidth, height() }, _contentScrollAddToY);
-		_sideShadow->setGeometryToLeft(dialogsWidth, 0, st::lineWidth, height());
+		const auto shadowTop = _controller->window().verticalShadowTop();
+		const auto shadowHeight = height() - shadowTop;
+		_sideShadow->setGeometryToLeft(
+			dialogsWidth, 
+			shadowTop,
+			st::lineWidth, 
+			shadowHeight);
 		if (_thirdShadow) {
 			_thirdShadow->setGeometryToLeft(
 				width() - thirdSectionWidth - st::lineWidth,
-				0,
+				shadowTop,
 				st::lineWidth,
-				height());
+				shadowHeight);
 		}
 		if (_callTopBar) {
 			_callTopBar->resizeToWidth(mainSectionWidth);
diff --git a/Telegram/SourceFiles/mainwindow.h b/Telegram/SourceFiles/mainwindow.h
index 15f3815f2a..4ca8e07f4b 100644
--- a/Telegram/SourceFiles/mainwindow.h
+++ b/Telegram/SourceFiles/mainwindow.h
@@ -63,8 +63,6 @@ public:
 
 	void checkHistoryActivation();
 
-	void fixOrder();
-
 	void sendPaths();
 
 	QImage iconWithCounter(int size, int count, style::color bg, style::color fg, bool smallIcon) override;
@@ -79,6 +77,7 @@ public:
 
 	void showMainMenu();
 	void updateTrayMenu(bool force = false) override;
+	void fixOrder() override;
 
 	void showSpecialLayer(
 		object_ptr<Ui::LayerWidget> layer,
diff --git a/Telegram/SourceFiles/platform/linux/window_title_linux.h b/Telegram/SourceFiles/platform/linux/window_title_linux.h
index 19b2e9d069..c9e58bbe64 100644
--- a/Telegram/SourceFiles/platform/linux/window_title_linux.h
+++ b/Telegram/SourceFiles/platform/linux/window_title_linux.h
@@ -22,14 +22,22 @@ void DefaultPreviewWindowFramePaint(QImage &preview, const style::palette &palet
 
 namespace Platform {
 
-inline object_ptr<Window::TitleWidget> CreateTitleWidget(QWidget *parent) {
+inline bool AllowNativeWindowFrameToggle() {
 #if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0) || defined DESKTOP_APP_QT_PATCHED
-	if (!DesktopEnvironment::IsUnity()) {
-		return object_ptr<Window::TitleWidgetQt>(parent);
-	}
+	return !DesktopEnvironment::IsUnity();
+#else // Qt >= 5.15 || DESKTOP_APP_QT_PATCHED
+	return false;
 #endif // Qt >= 5.15 || DESKTOP_APP_QT_PATCHED
+}
 
-	return { nullptr };
+inline object_ptr<Window::TitleWidget> CreateTitleWidget(QWidget *parent) {
+	return AllowNativeWindowFrameToggle()
+		? object_ptr<Window::TitleWidgetQt>(parent)
+		: object_ptr<Window::TitleWidgetQt>{ nullptr };
+}
+
+inline bool NativeTitleRequiresShadow() {
+	return false;
 }
 
 inline int PreviewTitleHeight() {
diff --git a/Telegram/SourceFiles/platform/mac/window_title_mac.h b/Telegram/SourceFiles/platform/mac/window_title_mac.h
index bf7370c084..924f7a440d 100644
--- a/Telegram/SourceFiles/platform/mac/window_title_mac.h
+++ b/Telegram/SourceFiles/platform/mac/window_title_mac.h
@@ -32,8 +32,16 @@ private:
 
 };
 
+inline bool AllowNativeWindowFrameToggle() {
+	return false;
+}
+
 object_ptr<Window::TitleWidget> CreateTitleWidget(QWidget *parent);
 
+inline bool NativeTitleRequiresShadow() {
+	return false;
+}
+
 int PreviewTitleHeight();
 void PreviewWindowFramePaint(QImage &preview, const style::palette &palette, QRect body, int outerWidth);
 
diff --git a/Telegram/SourceFiles/platform/platform_window_title.h b/Telegram/SourceFiles/platform/platform_window_title.h
index 1af12c8256..cd6b3a631b 100644
--- a/Telegram/SourceFiles/platform/platform_window_title.h
+++ b/Telegram/SourceFiles/platform/platform_window_title.h
@@ -14,7 +14,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 namespace Platform {
 
+bool AllowNativeWindowFrameToggle();
 object_ptr<Window::TitleWidget> CreateTitleWidget(QWidget *parent);
+bool NativeTitleRequiresShadow();
 
 int PreviewTitleHeight();
 void PreviewWindowFramePaint(QImage &preview, const style::palette &palette, QRect body, int outerWidth);
@@ -33,12 +35,22 @@ void PreviewWindowFramePaint(QImage &preview, const style::palette &palette, QRe
 
 namespace Platform {
 
-inline object_ptr<Window::TitleWidget> CreateTitleWidget(QWidget *parent) {
+inline bool AllowNativeWindowFrameToggle() {
 #if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0) || defined DESKTOP_APP_QT_PATCHED
-	return object_ptr<Window::TitleWidgetQt>(parent);
+	return true;
+#else // Qt >= 5.15 || DESKTOP_APP_QT_PATCHED
+	return false;
 #endif // Qt >= 5.15 || DESKTOP_APP_QT_PATCHED
+}
 
-	return { nullptr };
+inline object_ptr<Window::TitleWidget> CreateTitleWidget(QWidget *parent) {
+	return AllowNativeWindowFrameToggle()
+		? object_ptr<Window::TitleWidgetQt>(parent)
+		: object_ptr<Window::TitleWidgetQt>{ nullptr };
+}
+
+inline bool NativeTitleRequiresShadow() {
+	return false;
 }
 
 inline int PreviewTitleHeight() {
diff --git a/Telegram/SourceFiles/platform/win/main_window_win.cpp b/Telegram/SourceFiles/platform/win/main_window_win.cpp
index dd2b44a7e6..0f2d114d12 100644
--- a/Telegram/SourceFiles/platform/win/main_window_win.cpp
+++ b/Telegram/SourceFiles/platform/win/main_window_win.cpp
@@ -112,6 +112,12 @@ MainWindow::MainWindow(not_null<Window::Controller*> controller)
 			_shadow->setColor(st::windowShadowFg->c);
 		}
 	});
+	Core::App().settings().nativeWindowFrameChanges(
+	) | rpl::start_with_next([=] {
+		initShadows();
+		validateWindowTheme();
+		fixMaximizedWindow();
+	}, lifetime());
 }
 
 void MainWindow::TaskbarCreated() {
@@ -231,6 +237,10 @@ void MainWindow::workmodeUpdated(DBIWorkMode mode) {
 	}
 }
 
+void MainWindow::updateWindowIcon() {
+	updateIconCounters();
+}
+
 void MainWindow::unreadCounterChangedHook() {
 	setWindowTitle(titleText());
 	updateIconCounters();
@@ -294,18 +304,24 @@ void MainWindow::initHook() {
 	}
 
 	psInitSysMenu();
-
-	_shadow.emplace(this, st::windowShadowFg->c);
 }
 
 void MainWindow::initShadows() {
-	psUpdateMargins();
-	shadowsUpdate(Ui::Platform::WindowShadow::Change::Hidden);
+	if (Core::App().settings().nativeWindowFrame()) {
+		_shadow.reset();
+	} else {
+		_shadow.emplace(this, st::windowShadowFg->c);
+	}
+	updateCustomMargins();
+	firstShadowsUpdate();
 }
 
 void MainWindow::firstShadowsUpdate() {
-	if (!(windowState() & Qt::WindowMinimized) && !isHidden()) {
-		using Change = Ui::Platform::WindowShadow::Change;
+	using Change = Ui::Platform::WindowShadow::Change;
+	if ((windowState() & (Qt::WindowMinimized | Qt::WindowMaximized))
+		|| isHidden()) {
+		shadowsUpdate(Change::Hidden);
+	} else {
 		shadowsUpdate(Change::Moved | Change::Resized | Change::Shown);
 	}
 }
@@ -363,19 +379,40 @@ void MainWindow::updateSystemMenu(Qt::WindowState state) {
 	}
 }
 
-void MainWindow::psUpdateMargins() {
-	if (!ps_hWnd || _inUpdateMargins) return;
+void MainWindow::updateCustomMargins() {
+	if (!ps_hWnd || _inUpdateMargins) {
+		return;
+	}
 
 	_inUpdateMargins = true;
 
-	RECT r, a;
+	const auto margins = computeCustomMargins();
+	if (const auto native = QGuiApplication::platformNativeInterface()) {
+		native->setWindowProperty(
+			windowHandle()->handle(),
+			qsl("WindowsCustomMargins"),
+			QVariant::fromValue<QMargins>(margins));
+	}
+	if (!_themeInited) {
+		_themeInited = true;
+		validateWindowTheme();
+	}
+	_inUpdateMargins = false;
+}
 
+QMargins MainWindow::computeCustomMargins() {
+	if (Core::App().settings().nativeWindowFrame()) {
+		_deltaLeft = _deltaTop = _deltaRight = _deltaBottom = 0;
+		return QMargins();
+	}
+	auto r = RECT();
 	GetClientRect(ps_hWnd, &r);
-	a = r;
 
-	LONG style = GetWindowLongPtr(ps_hWnd, GWL_STYLE), styleEx = GetWindowLongPtr(ps_hWnd, GWL_EXSTYLE);
+	auto a = r;
+	const auto style = GetWindowLongPtr(ps_hWnd, GWL_STYLE);
+	const auto styleEx = GetWindowLongPtr(ps_hWnd, GWL_EXSTYLE);
 	AdjustWindowRectEx(&a, style, false, styleEx);
-	QMargins margins = QMargins(a.left - r.left, a.top - r.top, r.right - a.right, r.bottom - a.bottom);
+	auto margins = QMargins(a.left - r.left, a.top - r.top, r.right - a.right, r.bottom - a.bottom);
 	if (style & WS_MAXIMIZE) {
 		RECT w, m;
 		GetWindowRect(ps_hWnd, &w);
@@ -404,23 +441,39 @@ void MainWindow::psUpdateMargins() {
 		SetWindowPos(ps_hWnd, 0, 0, 0, w.right - w.left - _deltaLeft - _deltaRight, w.bottom - w.top - _deltaBottom - _deltaTop, SWP_NOMOVE | SWP_NOSENDCHANGING | SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOREPOSITION);
 		_deltaLeft = _deltaTop = _deltaRight = _deltaBottom = 0;
 	}
+	return margins;
+}
 
-	if (const auto native = QGuiApplication::platformNativeInterface()) {
-		native->setWindowProperty(
-			windowHandle()->handle(),
-			qsl("WindowsCustomMargins"),
-			QVariant::fromValue<QMargins>(margins));
+void MainWindow::validateWindowTheme() {
+	if (IsWindows8OrGreater()) {
+		return;
+	} else if (Dlls::SetWindowTheme != nullptr) {
+		if (Core::App().settings().nativeWindowFrame()) {
+			Dlls::SetWindowTheme(ps_hWnd, nullptr, nullptr);
+		} else {
+			Dlls::SetWindowTheme(ps_hWnd, L" ", L" ");
+		}
+		QApplication::setStyle(QStyleFactory::create(qsl("Windows")));
 	}
-	if (!_themeInited) {
-		_themeInited = true;
-		if (!IsWindows8OrGreater()) {
-			if (Dlls::SetWindowTheme != nullptr) {
-				Dlls::SetWindowTheme(ps_hWnd, L" ", L" ");
-				QApplication::setStyle(QStyleFactory::create(qsl("Windows")));
-			}
+}
+
+void MainWindow::fixMaximizedWindow() {
+	auto r = RECT();
+	GetClientRect(ps_hWnd, &r);
+	const auto style = GetWindowLongPtr(ps_hWnd, GWL_STYLE);
+	const auto styleEx = GetWindowLongPtr(ps_hWnd, GWL_EXSTYLE);
+	AdjustWindowRectEx(&r, style, false, styleEx);
+	if (style & WS_MAXIMIZE) {
+		auto w = RECT();
+		GetWindowRect(ps_hWnd, &w);
+		if (const auto hMonitor = MonitorFromRect(&w, MONITOR_DEFAULTTONEAREST)) {
+			MONITORINFO mi;
+			mi.cbSize = sizeof(mi);
+			GetMonitorInfo(hMonitor, &mi);
+			const auto m = mi.rcWork;
+			SetWindowPos(ps_hWnd, 0, 0, 0, m.right - m.left - _deltaLeft - _deltaRight, m.bottom - m.top - _deltaTop - _deltaBottom, SWP_NOMOVE | SWP_NOSENDCHANGING | SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOREPOSITION);
 		}
 	}
-	_inUpdateMargins = false;
 }
 
 HWND MainWindow::psHwnd() const {
diff --git a/Telegram/SourceFiles/platform/win/main_window_win.h b/Telegram/SourceFiles/platform/win/main_window_win.h
index 938565a0b6..d534f81e7b 100644
--- a/Telegram/SourceFiles/platform/win/main_window_win.h
+++ b/Telegram/SourceFiles/platform/win/main_window_win.h
@@ -31,7 +31,9 @@ public:
 
 	void psInitSysMenu();
 	void updateSystemMenu(Qt::WindowState state);
-	void psUpdateMargins();
+	void updateCustomMargins();
+
+	void updateWindowIcon() override;
 
 	void psRefreshTaskbarIcon();
 
@@ -89,8 +91,10 @@ protected:
 
 private:
 	void updateIconCounters();
-
+	QMargins computeCustomMargins();
+	void validateWindowTheme();
 	void psDestroyIcons();
+	void fixMaximizedWindow();
 
 	static UINT _taskbarCreatedMsgId;
 
diff --git a/Telegram/SourceFiles/platform/win/window_title_win.h b/Telegram/SourceFiles/platform/win/window_title_win.h
index 3423857a79..9508e508b4 100644
--- a/Telegram/SourceFiles/platform/win/window_title_win.h
+++ b/Telegram/SourceFiles/platform/win/window_title_win.h
@@ -59,10 +59,18 @@ private:
 
 };
 
+inline bool AllowNativeWindowFrameToggle() {
+	return true;
+}
+
 inline object_ptr<Window::TitleWidget> CreateTitleWidget(QWidget *parent) {
 	return object_ptr<TitleWidget>(parent);
 }
 
+inline bool NativeTitleRequiresShadow() {
+	return true;
+}
+
 inline int PreviewTitleHeight() {
 	return Window::Theme::DefaultPreviewTitleHeight();
 }
diff --git a/Telegram/SourceFiles/platform/win/windows_event_filter.cpp b/Telegram/SourceFiles/platform/win/windows_event_filter.cpp
index 53b79ecdd3..6f0d8f901c 100644
--- a/Telegram/SourceFiles/platform/win/windows_event_filter.cpp
+++ b/Telegram/SourceFiles/platform/win/windows_event_filter.cpp
@@ -78,6 +78,79 @@ bool EventFilter::nativeEventFilter(
 	});
 }
 
+bool EventFilter::customWindowFrameEvent(
+		HWND hWnd,
+		UINT msg,
+		WPARAM wParam,
+		LPARAM lParam,
+		LRESULT *result) {
+	switch (msg) {
+	case WM_NCPAINT: {
+		if (QSysInfo::WindowsVersion >= QSysInfo::WV_WINDOWS8) return false;
+		if (result) *result = 0;
+	} return true;
+
+	case WM_NCCALCSIZE: {
+		WINDOWPLACEMENT wp;
+		wp.length = sizeof(WINDOWPLACEMENT);
+		if (GetWindowPlacement(hWnd, &wp) && wp.showCmd == SW_SHOWMAXIMIZED) {
+			LPNCCALCSIZE_PARAMS params = (LPNCCALCSIZE_PARAMS)lParam;
+			LPRECT r = (wParam == TRUE) ? &params->rgrc[0] : (LPRECT)lParam;
+			HMONITOR hMonitor = MonitorFromPoint({ (r->left + r->right) / 2, (r->top + r->bottom) / 2 }, MONITOR_DEFAULTTONEAREST);
+			if (hMonitor) {
+				MONITORINFO mi;
+				mi.cbSize = sizeof(mi);
+				if (GetMonitorInfo(hMonitor, &mi)) {
+					*r = mi.rcWork;
+				}
+			}
+		}
+		if (result) *result = 0;
+		return true;
+	}
+
+	case WM_NCACTIVATE: {
+		if (IsCompositionEnabled()) {
+			const auto res = DefWindowProc(hWnd, msg, wParam, -1);
+			if (result) *result = res;
+		} else {
+			// Thanks https://github.com/melak47/BorderlessWindow
+			if (result) *result = 1;
+		}
+	} return true;
+
+	case WM_NCHITTEST: {
+		if (!result) return false;
+
+		POINTS p = MAKEPOINTS(lParam);
+		RECT r;
+		GetWindowRect(hWnd, &r);
+		auto res = _window->hitTest(QPoint(p.x - r.left + _window->deltaLeft(), p.y - r.top + _window->deltaTop()));
+		switch (res) {
+		case Window::HitTestResult::Client:
+		case Window::HitTestResult::SysButton:   *result = HTCLIENT; break;
+		case Window::HitTestResult::Caption:     *result = HTCAPTION; break;
+		case Window::HitTestResult::Top:         *result = HTTOP; break;
+		case Window::HitTestResult::TopRight:    *result = HTTOPRIGHT; break;
+		case Window::HitTestResult::Right:       *result = HTRIGHT; break;
+		case Window::HitTestResult::BottomRight: *result = HTBOTTOMRIGHT; break;
+		case Window::HitTestResult::Bottom:      *result = HTBOTTOM; break;
+		case Window::HitTestResult::BottomLeft:  *result = HTBOTTOMLEFT; break;
+		case Window::HitTestResult::Left:        *result = HTLEFT; break;
+		case Window::HitTestResult::TopLeft:     *result = HTTOPLEFT; break;
+		case Window::HitTestResult::None:
+		default:                                 *result = HTTRANSPARENT; break;
+		};
+	} return true;
+
+	case WM_NCRBUTTONUP: {
+		SendMessage(hWnd, WM_SYSCOMMAND, SC_MOUSEMENU, lParam);
+	} return true;
+	}
+
+	return false;
+}
+
 bool EventFilter::mainWindowEvent(
 		HWND hWnd,
 		UINT msg,
@@ -92,6 +165,12 @@ bool EventFilter::mainWindowEvent(
 		}
 	}
 
+	if (!Core::App().settings().nativeWindowFrame()) {
+		if (customWindowFrameEvent(hWnd, msg, wParam, lParam, result)) {
+			return true;
+		}
+	}
+
 	switch (msg) {
 
 	case WM_TIMECHANGE: {
@@ -124,40 +203,6 @@ bool EventFilter::mainWindowEvent(
 		}
 	} return false;
 
-	case WM_NCPAINT: {
-		if (QSysInfo::WindowsVersion >= QSysInfo::WV_WINDOWS8) return false;
-		if (result) *result = 0;
-	} return true;
-
-	case WM_NCCALCSIZE: {
-		WINDOWPLACEMENT wp;
-		wp.length = sizeof(WINDOWPLACEMENT);
-		if (GetWindowPlacement(hWnd, &wp) && wp.showCmd == SW_SHOWMAXIMIZED) {
-			LPNCCALCSIZE_PARAMS params = (LPNCCALCSIZE_PARAMS)lParam;
-			LPRECT r = (wParam == TRUE) ? &params->rgrc[0] : (LPRECT)lParam;
-			HMONITOR hMonitor = MonitorFromPoint({ (r->left + r->right) / 2, (r->top + r->bottom) / 2 }, MONITOR_DEFAULTTONEAREST);
-			if (hMonitor) {
-				MONITORINFO mi;
-				mi.cbSize = sizeof(mi);
-				if (GetMonitorInfo(hMonitor, &mi)) {
-					*r = mi.rcWork;
-				}
-			}
-		}
-		if (result) *result = 0;
-		return true;
-	}
-
-	case WM_NCACTIVATE: {
-		if (IsCompositionEnabled()) {
-			const auto res = DefWindowProc(hWnd, msg, wParam, -1);
-			if (result) *result = res;
-		} else {
-			// Thanks https://github.com/melak47/BorderlessWindow
-			if (result) *result = 1;
-		}
-	} return true;
-
 	case WM_WINDOWPOSCHANGING:
 	case WM_WINDOWPOSCHANGED: {
 		WINDOWPLACEMENT wp;
@@ -182,7 +227,7 @@ bool EventFilter::mainWindowEvent(
 			} else {
 				_window->positionUpdated();
 			}
-			_window->psUpdateMargins();
+			_window->updateCustomMargins();
 			const auto changes = (wParam == SIZE_MINIMIZED || wParam == SIZE_MAXIMIZED) ? Change::Hidden : (Change::Resized | Change::Shown);
 			_window->shadowsUpdate(changes);
 		}
@@ -199,34 +244,6 @@ bool EventFilter::mainWindowEvent(
 		_window->positionUpdated();
 	} return false;
 
-	case WM_NCHITTEST: {
-		if (!result) return false;
-
-		POINTS p = MAKEPOINTS(lParam);
-		RECT r;
-		GetWindowRect(hWnd, &r);
-		auto res = _window->hitTest(QPoint(p.x - r.left + _window->deltaLeft(), p.y - r.top + _window->deltaTop()));
-		switch (res) {
-		case Window::HitTestResult::Client:
-		case Window::HitTestResult::SysButton:   *result = HTCLIENT; break;
-		case Window::HitTestResult::Caption:     *result = HTCAPTION; break;
-		case Window::HitTestResult::Top:         *result = HTTOP; break;
-		case Window::HitTestResult::TopRight:    *result = HTTOPRIGHT; break;
-		case Window::HitTestResult::Right:       *result = HTRIGHT; break;
-		case Window::HitTestResult::BottomRight: *result = HTBOTTOMRIGHT; break;
-		case Window::HitTestResult::Bottom:      *result = HTBOTTOM; break;
-		case Window::HitTestResult::BottomLeft:  *result = HTBOTTOMLEFT; break;
-		case Window::HitTestResult::Left:        *result = HTLEFT; break;
-		case Window::HitTestResult::TopLeft:     *result = HTTOPLEFT; break;
-		case Window::HitTestResult::None:
-		default:                                 *result = HTTRANSPARENT; break;
-		};
-	} return true;
-
-	case WM_NCRBUTTONUP: {
-		SendMessage(hWnd, WM_SYSCOMMAND, SC_MOUSEMENU, lParam);
-	} return true;
-
 	case WM_SYSCOMMAND: {
 		if (wParam == SC_MOUSEMENU) {
 			POINTS p = MAKEPOINTS(lParam);
diff --git a/Telegram/SourceFiles/platform/win/windows_event_filter.h b/Telegram/SourceFiles/platform/win/windows_event_filter.h
index 84ac63093c..a0dbd9d1e0 100644
--- a/Telegram/SourceFiles/platform/win/windows_event_filter.h
+++ b/Telegram/SourceFiles/platform/win/windows_event_filter.h
@@ -34,6 +34,13 @@ public:
 private:
 	explicit EventFilter(not_null<MainWindow*> window);
 
+	bool customWindowFrameEvent(
+		HWND hWnd,
+		UINT msg,
+		WPARAM wParam,
+		LPARAM lParam,
+		LRESULT *result);
+
 	not_null<MainWindow*> _window;
 	bool _sessionLoggedOff = false;
 
diff --git a/Telegram/SourceFiles/settings/settings_advanced.cpp b/Telegram/SourceFiles/settings/settings_advanced.cpp
index 5cd4af4575..7be2af484f 100644
--- a/Telegram/SourceFiles/settings/settings_advanced.cpp
+++ b/Telegram/SourceFiles/settings/settings_advanced.cpp
@@ -19,6 +19,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/about_box.h"
 #include "boxes/confirm_box.h"
 #include "platform/platform_specific.h"
+#include "platform/platform_window_title.h"
 #include "base/platform/base_platform_info.h"
 #include "window/window_session_controller.h"
 #include "lang/lang_keys.h"
@@ -407,6 +408,20 @@ void SetupTrayContent(not_null<Ui::VerticalLayout*> container) {
 		}, taskbar->lifetime());
 	}
 
+	if (Platform::AllowNativeWindowFrameToggle()) {
+		const auto nativeFrame = addCheckbox(
+			"Use system window frame",
+			Core::App().settings().nativeWindowFrame());
+
+		nativeFrame->checkedChanges(
+		) | rpl::filter([](bool checked) {
+			return (checked != Core::App().settings().nativeWindowFrame());
+		}) | rpl::start_with_next([=](bool checked) {
+			Core::App().settings().setNativeWindowFrame(checked);
+			Core::App().saveSettingsDelayed();
+		}, nativeFrame->lifetime());
+	}
+
 	if (Platform::AutostartSupported()) {
 		const auto minimizedToggled = [] {
 			return cStartMinimized() && !Global::LocalPasscode();
diff --git a/Telegram/SourceFiles/window/main_window.cpp b/Telegram/SourceFiles/window/main_window.cpp
index ff9b77f178..895c7c437b 100644
--- a/Telegram/SourceFiles/window/main_window.cpp
+++ b/Telegram/SourceFiles/window/main_window.cpp
@@ -26,6 +26,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/crc32hash.h"
 #include "base/call_delayed.h"
 #include "ui/toast/toast.h"
+#include "ui/widgets/shadow.h"
 #include "ui/ui_utility.h"
 #include "apiwrap.h"
 #include "mainwindow.h"
@@ -236,9 +237,14 @@ void MainWindow::init() {
 
 	updatePalette();
 
-	if ((_title = Platform::CreateTitleWidget(this))) {
-		_title->init();
+	if (Platform::AllowNativeWindowFrameToggle()) {
+		Core::App().settings().nativeWindowFrameChanges(
+		) | rpl::start_with_next([=](bool native) {
+			refreshTitleWidget();
+			recountGeometryConstraints();
+		}, lifetime());
 	}
+	refreshTitleWidget();
 
 	initSize();
 	updateUnreadCounter();
@@ -311,9 +317,34 @@ int MainWindow::computeMinHeight() const {
 	return title + outdated + st::windowMinHeight;
 }
 
-void MainWindow::initSize() {
+void MainWindow::refreshTitleWidget() {
+	if (Platform::AllowNativeWindowFrameToggle()
+		&& Core::App().settings().nativeWindowFrame()) {
+		_title.destroy();
+		if (Platform::NativeTitleRequiresShadow()) {
+			_titleShadow.create(this);
+			_titleShadow->show();
+		}
+	} else if ((_title = Platform::CreateTitleWidget(this))) {
+		_title->show();
+		_title->init();
+		_titleShadow.destroy();
+	}
+}
+
+void MainWindow::updateMinimumSize() {
 	setMinimumWidth(computeMinWidth());
 	setMinimumHeight(computeMinHeight());
+}
+
+void MainWindow::recountGeometryConstraints() {
+	updateMinimumSize();
+	updateControlsGeometry();
+	fixOrder();
+}
+
+void MainWindow::initSize() {
+	updateMinimumSize();
 
 	auto position = cWindowPos();
 	DEBUG_LOG(("Window Pos: Initializing first %1, %2, %3, %4 (maximized %5)").arg(position.x).arg(position.y).arg(position.w).arg(position.h).arg(Logs::b(position.maximized)));
@@ -425,6 +456,9 @@ void MainWindow::updateControlsGeometry() {
 		_title->setGeometry(0, bodyTop, width(), _title->height());
 		bodyTop += _title->height();
 	}
+	if (_titleShadow) {
+		_titleShadow->setGeometry(0, bodyTop, width(), st::lineWidth);
+	}
 	if (_outdated) {
 		Ui::SendPendingMoveResizeEvents(_outdated.data());
 		_outdated->resizeToWidth(width());
diff --git a/Telegram/SourceFiles/window/main_window.h b/Telegram/SourceFiles/window/main_window.h
index 52f5d58658..ceb6cdedac 100644
--- a/Telegram/SourceFiles/window/main_window.h
+++ b/Telegram/SourceFiles/window/main_window.h
@@ -21,6 +21,7 @@ class Account;
 
 namespace Ui {
 class BoxContent;
+class PlainShadow;
 } // namespace Ui
 
 namespace Window {
@@ -80,6 +81,8 @@ public:
 
 	virtual void updateTrayMenu(bool force = false) {
 	}
+	virtual void fixOrder() {
+	}
 
 	virtual ~MainWindow();
 
@@ -101,6 +104,7 @@ public:
 	int computeMinWidth() const;
 	int computeMinHeight() const;
 
+	void recountGeometryConstraints();
 	virtual void updateControlsGeometry();
 
 public slots:
@@ -173,6 +177,8 @@ protected:
 	void updateUnreadCounter();
 
 private:
+	void refreshTitleWidget();
+	void updateMinimumSize();
 	void updatePalette();
 	void initSize();
 
@@ -184,6 +190,7 @@ private:
 	bool _positionInited = false;
 
 	object_ptr<TitleWidget> _title = { nullptr };
+	object_ptr<Ui::PlainShadow> _titleShadow = { nullptr };
 	object_ptr<Ui::RpWidget> _outdated;
 	object_ptr<Ui::RpWidget> _body;
 	object_ptr<TWidget> _rightColumn = { nullptr };
diff --git a/Telegram/SourceFiles/window/window_controller.cpp b/Telegram/SourceFiles/window/window_controller.cpp
index 5868680279..479f645536 100644
--- a/Telegram/SourceFiles/window/window_controller.cpp
+++ b/Telegram/SourceFiles/window/window_controller.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "api/api_updates.h"
 #include "core/application.h"
 #include "core/click_handler_types.h"
+#include "platform/platform_window_title.h"
 #include "main/main_account.h"
 #include "main/main_domain.h"
 #include "main/main_session.h"
@@ -239,6 +240,13 @@ void Controller::showSettings() {
 	_widget.showSettings();
 }
 
+int Controller::verticalShadowTop() const {
+	return (Platform::NativeTitleRequiresShadow()
+		&& Core::App().settings().nativeWindowFrame())
+		? st::lineWidth
+		: 0;
+}
+
 void Controller::showToast(const QString &text) {
 	Ui::Toast::Show(_widget.bodyWidget(), text);
 }
@@ -255,9 +263,7 @@ void Controller::showRightColumn(object_ptr<TWidget> widget) {
 }
 
 void Controller::sideBarChanged() {
-	_widget.setMinimumWidth(_widget.computeMinWidth());
-	_widget.updateControlsGeometry();
-	_widget.fixOrder();
+	_widget.recountGeometryConstraints();
 }
 
 void Controller::activate() {
diff --git a/Telegram/SourceFiles/window/window_controller.h b/Telegram/SourceFiles/window/window_controller.h
index e5f14096fe..05c6e02fd5 100644
--- a/Telegram/SourceFiles/window/window_controller.h
+++ b/Telegram/SourceFiles/window/window_controller.h
@@ -48,6 +48,8 @@ public:
 
 	void showSettings();
 
+	[[nodiscard]] int verticalShadowTop() const;
+
 	template <typename BoxType>
 	QPointer<BoxType> show(
 			object_ptr<BoxType> content,
diff --git a/Telegram/lib_ui b/Telegram/lib_ui
index 09918f0133..aed9fe649b 160000
--- a/Telegram/lib_ui
+++ b/Telegram/lib_ui
@@ -1 +1 @@
-Subproject commit 09918f0133ce0070000b9ca2a798057e6ad8bd5d
+Subproject commit aed9fe649bc150d8f4c1404b61c6b8bd56192d1b