diff --git a/Telegram/CMakeLists.txt b/Telegram/CMakeLists.txt
index 7e56c73c2..3b4c44ffc 100644
--- a/Telegram/CMakeLists.txt
+++ b/Telegram/CMakeLists.txt
@@ -948,6 +948,8 @@ PRIVATE
     platform/linux/file_utilities_linux.h
     platform/linux/launcher_linux.cpp
     platform/linux/launcher_linux.h
+    platform/linux/integration_linux.cpp
+    platform/linux/integration_linux.h
     platform/linux/main_window_linux.cpp
     platform/linux/main_window_linux.h
     platform/linux/notifications_manager_linux_dummy.cpp
@@ -959,6 +961,8 @@ PRIVATE
     platform/mac/file_utilities_mac.h
     platform/mac/launcher_mac.mm
     platform/mac/launcher_mac.h
+    platform/mac/integration_mac.mm
+    platform/mac/integration_mac.h
     platform/mac/mac_iconv_helper.c
     platform/mac/main_window_mac.mm
     platform/mac/main_window_mac.h
@@ -993,6 +997,8 @@ PRIVATE
     platform/win/file_utilities_win.h
     platform/win/launcher_win.cpp
     platform/win/launcher_win.h
+    platform/win/integration_win.cpp
+    platform/win/integration_win.h
     platform/win/main_window_win.cpp
     platform/win/main_window_win.h
     platform/win/notifications_manager_win.cpp
@@ -1003,8 +1009,6 @@ PRIVATE
     platform/win/windows_app_user_model_id.h
     platform/win/windows_dlls.cpp
     platform/win/windows_dlls.h
-    platform/win/windows_event_filter.cpp
-    platform/win/windows_event_filter.h
     platform/win/windows_autostart_task.cpp
     platform/win/windows_autostart_task.h
     platform/win/windows_toast_activator.cpp
@@ -1012,6 +1016,8 @@ PRIVATE
     platform/platform_audio.h
     platform/platform_file_utilities.h
     platform/platform_launcher.h
+    platform/platform_integration.cpp
+    platform/platform_integration.h
     platform/platform_main_window.h
     platform/platform_notifications_manager.h
     platform/platform_specific.h
diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index b1e2278b9..7855d9c59 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -30,6 +30,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/platform/base_platform_last_input.h"
 #include "base/platform/base_platform_info.h"
 #include "platform/platform_specific.h"
+#include "platform/platform_integration.h"
 #include "mainwindow.h"
 #include "dialogs/dialogs_entry.h"
 #include "history/history.h"
@@ -130,6 +131,7 @@ Application::Application(not_null<Launcher*> launcher)
 : QObject()
 , _launcher(launcher)
 , _private(std::make_unique<Private>())
+, _platformIntegration(Platform::Integration::Create())
 , _databases(std::make_unique<Storage::Databases>())
 , _animationsManager(std::make_unique<Ui::Animations::Manager>())
 , _clearEmojiImageLoaderTimer([=] { clearEmojiSourceImages(); })
@@ -145,6 +147,8 @@ Application::Application(not_null<Launcher*> launcher)
 , _autoLockTimer([=] { checkAutoLock(); }) {
 	Ui::Integration::Set(&_private->uiIntegration);
 
+	_platformIntegration->init();
+
 	passcodeLockChanges(
 	) | rpl::start_with_next([=] {
 		_shouldLockAt = 0;
diff --git a/Telegram/SourceFiles/core/application.h b/Telegram/SourceFiles/core/application.h
index da8f1cf96..7dd72d81d 100644
--- a/Telegram/SourceFiles/core/application.h
+++ b/Telegram/SourceFiles/core/application.h
@@ -17,6 +17,10 @@ class MainWidget;
 class FileUploader;
 class Translator;
 
+namespace Platform {
+class Integration;
+} // namespace Platform
+
 namespace Storage {
 class Databases;
 } // namespace Storage
@@ -115,8 +119,11 @@ public:
 	Application &operator=(const Application &other) = delete;
 	~Application();
 
-	[[nodiscard]] not_null<Launcher*> launcher() const {
-		return _launcher;
+	[[nodiscard]] Launcher &launcher() const {
+		return *_launcher;
+	}
+	[[nodiscard]] Platform::Integration &platformIntegration() const {
+		return *_platformIntegration;
 	}
 
 	void run();
@@ -317,13 +324,13 @@ private:
 	};
 	InstanceSetter _setter = { this };
 
-	not_null<Launcher*> _launcher;
+	const not_null<Launcher*> _launcher;
 	rpl::event_stream<ProxyChange> _proxyChanges;
 
 	// Some fields are just moved from the declaration.
 	struct Private;
 	const std::unique_ptr<Private> _private;
-	Settings _settings;
+	const std::unique_ptr<Platform::Integration> _platformIntegration;
 
 	const std::unique_ptr<Storage::Databases> _databases;
 	const std::unique_ptr<Ui::Animations::Manager> _animationsManager;
diff --git a/Telegram/SourceFiles/platform/linux/integration_linux.cpp b/Telegram/SourceFiles/platform/linux/integration_linux.cpp
new file mode 100644
index 000000000..bb58615cd
--- /dev/null
+++ b/Telegram/SourceFiles/platform/linux/integration_linux.cpp
@@ -0,0 +1,9 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "platform/linux/integration_linux.h"
+
diff --git a/Telegram/SourceFiles/platform/linux/integration_linux.h b/Telegram/SourceFiles/platform/linux/integration_linux.h
new file mode 100644
index 000000000..73e006325
--- /dev/null
+++ b/Telegram/SourceFiles/platform/linux/integration_linux.h
@@ -0,0 +1,9 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
diff --git a/Telegram/SourceFiles/platform/mac/integration_mac.h b/Telegram/SourceFiles/platform/mac/integration_mac.h
new file mode 100644
index 000000000..73e006325
--- /dev/null
+++ b/Telegram/SourceFiles/platform/mac/integration_mac.h
@@ -0,0 +1,9 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
diff --git a/Telegram/SourceFiles/platform/mac/integration_mac.mm b/Telegram/SourceFiles/platform/mac/integration_mac.mm
new file mode 100644
index 000000000..91d22ce7f
--- /dev/null
+++ b/Telegram/SourceFiles/platform/mac/integration_mac.mm
@@ -0,0 +1,9 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "platform/mac/integration_mac.h"
+
diff --git a/Telegram/SourceFiles/platform/platform_integration.cpp b/Telegram/SourceFiles/platform/platform_integration.cpp
new file mode 100644
index 000000000..021024c6f
--- /dev/null
+++ b/Telegram/SourceFiles/platform/platform_integration.cpp
@@ -0,0 +1,43 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "platform/platform_integration.h"
+
+#ifdef Q_OS_MAC
+#include "platform/mac/integration_mac.h"
+#elif defined Q_OS_UNIX // Q_OS_MAC
+#include "platform/linux/integration_linux.h"
+#elif defined Q_OS_WINRT || defined Q_OS_WIN // Q_OS_MAC || Q_OS_UNIX
+#include "platform/win/integration_win.h"
+#endif // Q_OS_MAC || Q_OS_UNIX || Q_OS_WINRT || Q_OS_WIN
+
+namespace Platform {
+namespace {
+
+Integration *GlobalInstance/* = nullptr*/;
+
+} // namespace
+
+Integration::~Integration() {
+	GlobalInstance = nullptr;
+}
+
+std::unique_ptr<Integration> Integration::Create() {
+	Expects(GlobalInstance == nullptr);
+
+	auto result = CreateIntegration();
+	GlobalInstance = result.get();
+	return result;
+}
+
+Integration &Integration::Instance() {
+	Expects(GlobalInstance != nullptr);
+
+	return *GlobalInstance;
+};
+
+} // namespace Platform
diff --git a/Telegram/SourceFiles/platform/platform_integration.h b/Telegram/SourceFiles/platform/platform_integration.h
new file mode 100644
index 000000000..36ad0b7b7
--- /dev/null
+++ b/Telegram/SourceFiles/platform/platform_integration.h
@@ -0,0 +1,23 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+namespace Platform {
+
+class Integration {
+public:
+	virtual void init() {
+	}
+
+	virtual ~Integration();
+
+	[[nodiscard]] static std::unique_ptr<Integration> Create();
+	[[nodiscard]] static Integration &Instance();
+};
+
+} // namespace Platform
diff --git a/Telegram/SourceFiles/platform/win/integration_win.cpp b/Telegram/SourceFiles/platform/win/integration_win.cpp
new file mode 100644
index 000000000..0b0da418d
--- /dev/null
+++ b/Telegram/SourceFiles/platform/win/integration_win.cpp
@@ -0,0 +1,99 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "platform/win/integration_win.h"
+
+#include "platform/platform_integration.h"
+#include "platform/platform_specific.h"
+#include "core/application.h"
+#include "core/sandbox.h"
+#include "app.h"
+
+#include <QtCore/QCoreApplication>
+#include <QtCore/QAbstractNativeEventFilter>
+
+namespace Platform {
+namespace {
+
+class WindowsIntegration final
+	: public Integration
+	, public QAbstractNativeEventFilter {
+public:
+	void init() override;
+
+private:
+	bool nativeEventFilter(
+		const QByteArray &eventType,
+		void *message,
+		long *result) override;
+	bool processEvent(
+		HWND hWnd,
+		UINT msg,
+		WPARAM wParam,
+		LPARAM lParam,
+		LRESULT *result);
+
+};
+
+void WindowsIntegration::init() {
+	QCoreApplication::instance()->installNativeEventFilter(this);
+}
+
+bool WindowsIntegration::nativeEventFilter(
+		const QByteArray &eventType,
+		void *message,
+		long *result) {
+	return Core::Sandbox::Instance().customEnterFromEventLoop([&] {
+		const auto msg = static_cast<MSG*>(message);
+		return processEvent(
+			msg->hwnd,
+			msg->message,
+			msg->wParam,
+			msg->lParam,
+			(LRESULT*)result);
+	});
+}
+
+bool WindowsIntegration::processEvent(
+		HWND hWnd,
+		UINT msg,
+		WPARAM wParam,
+		LPARAM lParam,
+		LRESULT *result) {
+	switch (msg) {
+	case WM_ENDSESSION:
+		App::quit();
+		break;
+
+	case WM_TIMECHANGE:
+		Core::App().checkAutoLockIn(100);
+		break;
+
+	case WM_WTSSESSION_CHANGE:
+		if (wParam == WTS_SESSION_LOGOFF
+			|| wParam == WTS_SESSION_LOCK) {
+			Core::App().setScreenIsLocked(true);
+		} else if (wParam == WTS_SESSION_LOGON
+			|| wParam == WTS_SESSION_UNLOCK) {
+			Core::App().setScreenIsLocked(false);
+		}
+		break;
+
+	case WM_SETTINGCHANGE:
+		Core::App().settings().setSystemDarkMode(Platform::IsDarkMode());
+		break;
+	}
+	return false;
+}
+
+} // namespace
+
+std::unique_ptr<Integration> CreateIntegration() {
+	return std::make_unique<WindowsIntegration>();
+}
+
+} // namespace Platform
diff --git a/Telegram/SourceFiles/platform/win/integration_win.h b/Telegram/SourceFiles/platform/win/integration_win.h
new file mode 100644
index 000000000..11b203214
--- /dev/null
+++ b/Telegram/SourceFiles/platform/win/integration_win.h
@@ -0,0 +1,16 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+namespace Platform {
+
+class Integration;
+
+[[nodiscard]] std::unique_ptr<Integration> CreateIntegration();
+
+} // namespace Platform
diff --git a/Telegram/SourceFiles/platform/win/main_window_win.cpp b/Telegram/SourceFiles/platform/win/main_window_win.cpp
index 7a0a9ebd4..ccd341333 100644
--- a/Telegram/SourceFiles/platform/win/main_window_win.cpp
+++ b/Telegram/SourceFiles/platform/win/main_window_win.cpp
@@ -11,7 +11,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "platform/platform_specific.h"
 #include "platform/platform_notifications_manager.h"
 #include "platform/win/windows_dlls.h"
-#include "platform/win/windows_event_filter.h"
 #include "window/notifications_manager.h"
 #include "window/window_session_controller.h"
 #include "mainwindow.h"
@@ -20,6 +19,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/platform/win/base_windows_wrl.h"
 #include "base/platform/base_platform_info.h"
 #include "core/application.h"
+#include "core/sandbox.h"
 #include "lang/lang_keys.h"
 #include "storage/localstorage.h"
 #include "ui/widgets/popup_menu.h"
@@ -58,8 +58,33 @@ namespace {
 // icon click (both left or right button) was made from the active app.
 constexpr auto kKeepActiveForTrayIcon = crl::time(500);
 
+class EventFilter final : public QAbstractNativeEventFilter {
+public:
+	explicit EventFilter(not_null<MainWindow*> window);
+
+private:
+	bool nativeEventFilter(
+		const QByteArray &eventType,
+		void *message,
+		long *result) override;
+
+	bool mainWindowEvent(
+		HWND hWnd,
+		UINT msg,
+		WPARAM wParam,
+		LPARAM lParam,
+		LRESULT *result);
+
+	const not_null<MainWindow*> _window;
+
+};
+
 using namespace Microsoft::WRL;
 
+ComPtr<ITaskbarList3> taskbarList;
+bool handleSessionNotification = false;
+uint32 kTaskbarCreatedMsgId = 0;
+
 [[nodiscard]] HICON NativeIcon(const QIcon &icon, QSize size) {
 	if (!icon.isNull()) {
 		const auto pixmap = icon.pixmap(icon.actualSize(size));
@@ -133,22 +158,88 @@ using namespace Microsoft::WRL;
 	return result;
 }
 
-ComPtr<ITaskbarList3> taskbarList;
-bool handleSessionNotification = false;
-uint32 kTaskbarCreatedMsgId = 0;
+EventFilter::EventFilter(not_null<MainWindow*> window) : _window(window) {
+}
+
+bool EventFilter::nativeEventFilter(
+		const QByteArray &eventType,
+		void *message,
+		long *result) {
+	return Core::Sandbox::Instance().customEnterFromEventLoop([&] {
+		const auto msg = static_cast<MSG*>(message);
+		if (msg->hwnd == _window->psHwnd()
+			|| msg->hwnd && !_window->psHwnd()) {
+			return mainWindowEvent(
+				msg->hwnd,
+				msg->message,
+				msg->wParam,
+				msg->lParam,
+				(LRESULT*)result);
+		}
+		return false;
+	});
+}
+
+bool EventFilter::mainWindowEvent(
+		HWND hWnd,
+		UINT msg,
+		WPARAM wParam,
+		LPARAM lParam,
+		LRESULT *result) {
+	if (const auto tbCreatedMsgId = kTaskbarCreatedMsgId) {
+		if (msg == tbCreatedMsgId) {
+			HRESULT hr = CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_ALL, IID_PPV_ARGS(&taskbarList));
+			if (!SUCCEEDED(hr)) {
+				taskbarList.Reset();
+			}
+		}
+	}
+
+	switch (msg) {
+
+	case WM_DESTROY: {
+		_window->destroyedFromSystem();
+	} return false;
+
+	case WM_ACTIVATE: {
+		if (LOWORD(wParam) != WA_INACTIVE) {
+			_window->shadowsActivate();
+		} else {
+			_window->shadowsDeactivate();
+		}
+	} return false;
+
+	case WM_SIZE: {
+		if (wParam == SIZE_MAXIMIZED || wParam == SIZE_RESTORED || wParam == SIZE_MINIMIZED) {
+			if (wParam == SIZE_RESTORED && _window->windowState() == Qt::WindowNoState) {
+				_window->positionUpdated();
+			}
+		}
+	} return false;
+
+	case WM_MOVE: {
+		_window->positionUpdated();
+	} return false;
+
+	}
+	return false;
+}
 
 } // namespace
 
 struct MainWindow::Private {
+	explicit Private(not_null<MainWindow*> window) : filter(window) {
+	}
+
+	EventFilter filter;
 	ComPtr<ViewManagement::IUIViewSettings> viewSettings;
 };
 
 MainWindow::MainWindow(not_null<Window::Controller*> controller)
 : Window::MainWindow(controller)
-, _private(std::make_unique<Private>())
+, _private(std::make_unique<Private>(this))
 , _taskbarHiderWindow(std::make_unique<QWindow>()) {
-	QCoreApplication::instance()->installNativeEventFilter(
-		EventFilter::CreateInstance(this));
+	qApp->installNativeEventFilter(&_private->filter);
 
 	if (!kTaskbarCreatedMsgId) {
 		kTaskbarCreatedMsgId = RegisterWindowMessage(L"TaskbarButtonCreated");
@@ -178,17 +269,6 @@ void MainWindow::setupNativeWindowFrame() {
 	}, lifetime());
 }
 
-uint32 MainWindow::TaskbarCreatedMsgId() {
-	return kTaskbarCreatedMsgId;
-}
-
-void MainWindow::TaskbarCreated() {
-	HRESULT hr = CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_ALL, IID_PPV_ARGS(&taskbarList));
-	if (!SUCCEEDED(hr)) {
-		taskbarList.Reset();
-	}
-}
-
 void MainWindow::shadowsActivate() {
 	_hasActiveFrame = true;
 }
@@ -201,6 +281,10 @@ void MainWindow::psShowTrayMenu() {
 	trayIconMenu->popup(QCursor::pos());
 }
 
+void MainWindow::destroyedFromSystem() {
+	App::quit();
+}
+
 int32 MainWindow::screenNameChecksum(const QString &name) const {
 	constexpr int DeviceNameSize = base::array_size(MONITORINFOEX().szDevice);
 	wchar_t buffer[DeviceNameSize] = { 0 };
@@ -212,7 +296,7 @@ int32 MainWindow::screenNameChecksum(const QString &name) const {
 	return base::crc32(buffer, sizeof(buffer));
 }
 
-void MainWindow::psRefreshTaskbarIcon() {
+void MainWindow::forceIconRefresh() {
 	const auto refresher = std::make_unique<QWidget>(this);
 	refresher->setWindowFlags(static_cast<Qt::WindowFlags>(Qt::Tool) | Qt::FramelessWindowHint);
 	refresher->setGeometry(x() + 1, y() + 1, 1, 1);
@@ -267,20 +351,20 @@ void MainWindow::workmodeUpdated(Core::Settings::WorkMode mode) {
 	switch (mode) {
 	case WorkMode::WindowAndTray: {
 		psSetupTrayIcon();
-		HWND psOwner = (HWND)GetWindowLongPtr(ps_hWnd, GWLP_HWNDPARENT);
+		HWND psOwner = (HWND)GetWindowLongPtr(_hWnd, GWLP_HWNDPARENT);
 		if (psOwner) {
-			SetWindowLongPtr(ps_hWnd, GWLP_HWNDPARENT, 0);
+			SetWindowLongPtr(_hWnd, GWLP_HWNDPARENT, 0);
 			windowHandle()->setTransientParent(nullptr);
-			psRefreshTaskbarIcon();
+			forceIconRefresh();
 		}
 	} break;
 
 	case WorkMode::TrayOnly: {
 		psSetupTrayIcon();
-		HWND psOwner = (HWND)GetWindowLongPtr(ps_hWnd, GWLP_HWNDPARENT);
+		HWND psOwner = (HWND)GetWindowLongPtr(_hWnd, GWLP_HWNDPARENT);
 		if (!psOwner) {
 			const auto hwnd = _taskbarHiderWindow->winId();
-			SetWindowLongPtr(ps_hWnd, GWLP_HWNDPARENT, (LONG_PTR)hwnd);
+			SetWindowLongPtr(_hWnd, GWLP_HWNDPARENT, (LONG_PTR)hwnd);
 			windowHandle()->setTransientParent(_taskbarHiderWindow.get());
 		}
 	} break;
@@ -292,11 +376,11 @@ void MainWindow::workmodeUpdated(Core::Settings::WorkMode mode) {
 		}
 		trayIcon = 0;
 
-		HWND psOwner = (HWND)GetWindowLongPtr(ps_hWnd, GWLP_HWNDPARENT);
+		HWND psOwner = (HWND)GetWindowLongPtr(_hWnd, GWLP_HWNDPARENT);
 		if (psOwner) {
-			SetWindowLongPtr(ps_hWnd, GWLP_HWNDPARENT, 0);
+			SetWindowLongPtr(_hWnd, GWLP_HWNDPARENT, 0);
 			windowHandle()->setTransientParent(nullptr);
-			psRefreshTaskbarIcon();
+			forceIconRefresh();
 		}
 	} break;
 	}
@@ -403,11 +487,11 @@ void MainWindow::updateIconCounters() {
 		trayIcon->setIcon(forTrayIcon);
 	}
 
-	psDestroyIcons();
-	ps_iconSmall = NativeIcon(iconSmall, iconSizeSmall);
-	ps_iconBig = NativeIcon(iconBig, iconSizeBig);
-	SendMessage(ps_hWnd, WM_SETICON, ICON_SMALL, (LPARAM)ps_iconSmall);
-	SendMessage(ps_hWnd, WM_SETICON, ICON_BIG, (LPARAM)(ps_iconBig ? ps_iconBig : ps_iconSmall));
+	destroyCachedIcons();
+	_iconSmall = NativeIcon(iconSmall, iconSizeSmall);
+	_iconBig = NativeIcon(iconBig, iconSizeBig);
+	SendMessage(_hWnd, WM_SETICON, ICON_SMALL, (LPARAM)_iconSmall);
+	SendMessage(_hWnd, WM_SETICON, ICON_BIG, (LPARAM)(_iconBig ? _iconBig : _iconSmall));
 	if (taskbarList) {
 		if (counter > 0) {
 			const auto pixmap = [&](int size) {
@@ -417,27 +501,23 @@ void MainWindow::updateIconCounters() {
 			QIcon iconOverlay;
 			iconOverlay.addPixmap(pixmap(16));
 			iconOverlay.addPixmap(pixmap(32));
-			ps_iconOverlay = NativeIcon(iconOverlay, iconSizeSmall);
+			_iconOverlay = NativeIcon(iconOverlay, iconSizeSmall);
 		}
 		const auto description = (counter > 0)
 			? tr::lng_unread_bar(tr::now, lt_count, counter).toStdWString()
 			: std::wstring();
-		taskbarList->SetOverlayIcon(ps_hWnd, ps_iconOverlay, description.c_str());
+		taskbarList->SetOverlayIcon(_hWnd, _iconOverlay, description.c_str());
 	}
-	SetWindowPos(ps_hWnd, 0, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOACTIVATE);
+	SetWindowPos(_hWnd, 0, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOACTIVATE);
 }
 
 void MainWindow::initHook() {
-	ps_hWnd = reinterpret_cast<HWND>(winId());
-	if (!ps_hWnd) {
+	_hWnd = reinterpret_cast<HWND>(winId());
+	if (!_hWnd) {
 		return;
 	}
 
-	handleSessionNotification = (Dlls::WTSRegisterSessionNotification != nullptr)
-		&& (Dlls::WTSUnRegisterSessionNotification != nullptr);
-	if (handleSessionNotification) {
-		Dlls::WTSRegisterSessionNotification(ps_hWnd, NOTIFY_FOR_THIS_SESSION);
-	}
+	WTSRegisterSessionNotification(_hWnd, NOTIFY_FOR_THIS_SESSION);
 
 	using namespace base::Platform;
 	auto factory = ComPtr<IUIViewSettingsInterop>();
@@ -449,7 +529,7 @@ void MainWindow::initHook() {
 		if (factory) {
 			// NB! No such method (or IUIViewSettingsInterop) in C++/WinRT :(
 			factory->GetForWindow(
-				ps_hWnd,
+				_hWnd,
 				IID_PPV_ARGS(&_private->viewSettings));
 		}
 	}
@@ -462,7 +542,7 @@ void MainWindow::initHook() {
 void MainWindow::validateWindowTheme(bool native, bool night) {
 	if (!IsWindows8OrGreater()) {
 		const auto empty = native ? nullptr : L" ";
-		SetWindowTheme(ps_hWnd, empty, empty);
+		SetWindowTheme(_hWnd, empty, empty);
 		QApplication::setStyle(QStyleFactory::create(u"Windows"_q));
 #if 0
 	} else if (!Platform::IsDarkModeSupported()/*
@@ -473,7 +553,7 @@ void MainWindow::validateWindowTheme(bool native, bool night) {
 		return;
 #endif
 	} else if (!native) {
-		SetWindowTheme(ps_hWnd, nullptr, nullptr);
+		SetWindowTheme(_hWnd, nullptr, nullptr);
 		return;
 	}
 
@@ -491,13 +571,13 @@ void MainWindow::validateWindowTheme(bool native, bool night) {
 				&darkValue,
 				sizeof(darkValue)
 			};
-			Dlls::SetWindowCompositionAttribute(ps_hWnd, &data);
+			Dlls::SetWindowCompositionAttribute(_hWnd, &data);
 		} else if (kSystemVersion.microVersion() >= 17763) {
 			static const auto kDWMWA_USE_IMMERSIVE_DARK_MODE = (kSystemVersion.microVersion() >= 18985)
 				? DWORD(20)
 				: DWORD(19);
 			DwmSetWindowAttribute(
-				ps_hWnd,
+				_hWnd,
 				kDWMWA_USE_IMMERSIVE_DARK_MODE,
 				&darkValue,
 				sizeof(darkValue));
@@ -514,7 +594,7 @@ void MainWindow::validateWindowTheme(bool native, bool night) {
 
 	//const auto updateWindowTheme = [&] {
 	//	const auto set = [&](LPCWSTR name) {
-	//		return SetWindowTheme(ps_hWnd, name, nullptr);
+	//		return SetWindowTheme(_hWnd, name, nullptr);
 	//	};
 	//	if (!night || FAILED(set(L"DarkMode_Explorer"))) {
 	//		set(L"Explorer");
@@ -527,14 +607,14 @@ void MainWindow::validateWindowTheme(bool native, bool night) {
 	//	} else {
 	//		Dlls::AllowDarkModeForApp(TRUE);
 	//	}
-	//	Dlls::AllowDarkModeForWindow(ps_hWnd, TRUE);
+	//	Dlls::AllowDarkModeForWindow(_hWnd, TRUE);
 	//	updateWindowTheme();
 	//	updateStyle();
 	//	Dlls::FlushMenuThemes();
 	//	Dlls::RefreshImmersiveColorPolicyState();
 	//} else {
 	//	updateWindowTheme();
-	//	Dlls::AllowDarkModeForWindow(ps_hWnd, FALSE);
+	//	Dlls::AllowDarkModeForWindow(_hWnd, FALSE);
 	//	updateStyle();
 	//	Dlls::FlushMenuThemes();
 	//	Dlls::RefreshImmersiveColorPolicyState();
@@ -546,8 +626,8 @@ void MainWindow::validateWindowTheme(bool native, bool night) {
 	//}
 
 	// Didn't find any other way to definitely repaint with the new style.
-	SendMessage(ps_hWnd, WM_NCACTIVATE, _hasActiveFrame ? 0 : 1, 0);
-	SendMessage(ps_hWnd, WM_NCACTIVATE, _hasActiveFrame ? 1 : 0, 0);
+	SendMessage(_hWnd, WM_NCACTIVATE, _hasActiveFrame ? 0 : 1, 0);
+	SendMessage(_hWnd, WM_NCACTIVATE, _hasActiveFrame ? 1 : 0, 0);
 }
 
 void MainWindow::showFromTrayMenu() {
@@ -562,36 +642,28 @@ void MainWindow::showFromTrayMenu() {
 }
 
 HWND MainWindow::psHwnd() const {
-	return ps_hWnd;
+	return _hWnd;
 }
 
-void MainWindow::psDestroyIcons() {
-	if (ps_iconBig) {
-		DestroyIcon(ps_iconBig);
-		ps_iconBig = 0;
-	}
-	if (ps_iconSmall) {
-		DestroyIcon(ps_iconSmall);
-		ps_iconSmall = 0;
-	}
-	if (ps_iconOverlay) {
-		DestroyIcon(ps_iconOverlay);
-		ps_iconOverlay = 0;
-	}
+void MainWindow::destroyCachedIcons() {
+	const auto destroy = [](HICON &icon) {
+		if (icon) {
+			DestroyIcon(icon);
+			icon = nullptr;
+		}
+	};
+	destroy(_iconBig);
+	destroy(_iconSmall);
+	destroy(_iconOverlay);
 }
 
 MainWindow::~MainWindow() {
-	if (handleSessionNotification) {
-		Dlls::WTSUnRegisterSessionNotification(ps_hWnd);
-	}
+	WTSUnRegisterSessionNotification(_hWnd);
 	_private->viewSettings.Reset();
 	if (taskbarList) {
 		taskbarList.Reset();
 	}
-
-	psDestroyIcons();
-
-	EventFilter::Destroy();
+	destroyCachedIcons();
 }
 
 } // namespace Platform
diff --git a/Telegram/SourceFiles/platform/win/main_window_win.h b/Telegram/SourceFiles/platform/win/main_window_win.h
index 02a6efd62..09a801524 100644
--- a/Telegram/SourceFiles/platform/win/main_window_win.h
+++ b/Telegram/SourceFiles/platform/win/main_window_win.h
@@ -28,11 +28,6 @@ public:
 	void updateWindowIcon() override;
 	bool isActiveForTrayMenu() override;
 
-	void psRefreshTaskbarIcon();
-
-	[[nodiscard]] static uint32 TaskbarCreatedMsgId();
-	static void TaskbarCreated();
-
 	// Custom shadows.
 	void shadowsActivate();
 	void shadowsDeactivate();
@@ -41,6 +36,8 @@ public:
 
 	void psShowTrayMenu();
 
+	void destroyedFromSystem();
+
 	~MainWindow();
 
 protected:
@@ -72,22 +69,23 @@ private:
 	void setupNativeWindowFrame();
 	void updateIconCounters();
 	void validateWindowTheme(bool native, bool night);
-	void psDestroyIcons();
+
+	void forceIconRefresh();
+	void destroyCachedIcons();
 
 	const std::unique_ptr<Private> _private;
+	const std::unique_ptr<QWindow> _taskbarHiderWindow;
 
-	bool _hasActiveFrame = false;
+	HWND _hWnd = nullptr;
+	HICON _iconBig = nullptr;
+	HICON _iconSmall = nullptr;
+	HICON _iconOverlay = nullptr;
 
 	// Workarounds for activation from tray icon.
 	crl::time _lastDeactivateTime = 0;
 	rpl::lifetime _showFromTrayLifetime;
 
-	HWND ps_hWnd = nullptr;
-	HICON ps_iconBig = nullptr;
-	HICON ps_iconSmall = nullptr;
-	HICON ps_iconOverlay = nullptr;
-
-	const std::unique_ptr<QWindow> _taskbarHiderWindow;
+	bool _hasActiveFrame = false;
 
 };
 
diff --git a/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp b/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp
index b761b06fa..eebe67cdf 100644
--- a/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp
+++ b/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp
@@ -16,7 +16,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/qthelp_url.h"
 #include "platform/win/windows_app_user_model_id.h"
 #include "platform/win/windows_toast_activator.h"
-#include "platform/win/windows_event_filter.h"
 #include "platform/win/windows_dlls.h"
 #include "platform/win/specific_win.h"
 #include "history/history.h"
diff --git a/Telegram/SourceFiles/platform/win/windows_dlls.cpp b/Telegram/SourceFiles/platform/win/windows_dlls.cpp
index 4d2e75309..f728fcce2 100644
--- a/Telegram/SourceFiles/platform/win/windows_dlls.cpp
+++ b/Telegram/SourceFiles/platform/win/windows_dlls.cpp
@@ -53,10 +53,6 @@ SafeIniter::SafeIniter() {
 	//	}
 	//}
 
-	const auto LibWtsApi32 = LoadLibrary(L"wtsapi32.dll");
-	LOAD_SYMBOL(LibWtsApi32, WTSRegisterSessionNotification);
-	LOAD_SYMBOL(LibWtsApi32, WTSUnRegisterSessionNotification);
-
 	const auto LibPropSys = LoadLibrary(L"propsys.dll");
 	LOAD_SYMBOL(LibPropSys, PSStringFromPropertyKey);
 
diff --git a/Telegram/SourceFiles/platform/win/windows_dlls.h b/Telegram/SourceFiles/platform/win/windows_dlls.h
index 4579c8ce9..b3695f269 100644
--- a/Telegram/SourceFiles/platform/win/windows_dlls.h
+++ b/Telegram/SourceFiles/platform/win/windows_dlls.h
@@ -68,14 +68,6 @@ inline void(__stdcall *SHChangeNotify)(
 inline HRESULT(__stdcall *SetCurrentProcessExplicitAppUserModelID)(
 	__in PCWSTR AppID);
 
-// WTSAPI32.DLL
-
-inline BOOL(__stdcall *WTSRegisterSessionNotification)(
-	HWND hWnd,
-	DWORD dwFlags);
-inline BOOL(__stdcall *WTSUnRegisterSessionNotification)(
-	HWND hWnd);
-
 // PROPSYS.DLL
 
 inline HRESULT(__stdcall *PSStringFromPropertyKey)(
diff --git a/Telegram/SourceFiles/platform/win/windows_event_filter.cpp b/Telegram/SourceFiles/platform/win/windows_event_filter.cpp
deleted file mode 100644
index 4d0127bbb..000000000
--- a/Telegram/SourceFiles/platform/win/windows_event_filter.cpp
+++ /dev/null
@@ -1,123 +0,0 @@
-/*
-This file is part of Telegram Desktop,
-the official desktop application for the Telegram messaging service.
-
-For license and copyright information please follow this link:
-https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
-*/
-#include "platform/win/windows_event_filter.h"
-
-#include "platform/win/specific_win.h"
-#include "core/sandbox.h"
-#include "core/core_settings.h"
-#include "core/application.h"
-#include "mainwindow.h"
-#include "app.h"
-
-#include <QtGui/QWindow>
-
-namespace Platform {
-namespace {
-
-EventFilter *instance = nullptr;
-
-} // namespace
-
-EventFilter *EventFilter::CreateInstance(not_null<MainWindow*> window) {
-	Expects(instance == nullptr);
-
-	return (instance = new EventFilter(window));
-}
-
-void EventFilter::Destroy() {
-	Expects(instance != nullptr);
-
-	delete instance;
-	instance = nullptr;
-}
-
-EventFilter::EventFilter(not_null<MainWindow*> window) : _window(window) {
-}
-
-bool EventFilter::nativeEventFilter(
-		const QByteArray &eventType,
-		void *message,
-		long *result) {
-	return Core::Sandbox::Instance().customEnterFromEventLoop([&] {
-		const auto msg = static_cast<MSG*>(message);
-		if (msg->message == WM_ENDSESSION) {
-			App::quit();
-			return false;
-		}
-		if (msg->hwnd == _window->psHwnd()
-			|| msg->hwnd && !_window->psHwnd()) {
-			return mainWindowEvent(
-				msg->hwnd,
-				msg->message,
-				msg->wParam,
-				msg->lParam,
-				(LRESULT*)result);
-		}
-		return false;
-	});
-}
-
-bool EventFilter::mainWindowEvent(
-		HWND hWnd,
-		UINT msg,
-		WPARAM wParam,
-		LPARAM lParam,
-		LRESULT *result) {
-	if (const auto tbCreatedMsgId = Platform::MainWindow::TaskbarCreatedMsgId()) {
-		if (msg == tbCreatedMsgId) {
-			Platform::MainWindow::TaskbarCreated();
-		}
-	}
-
-	switch (msg) {
-
-	case WM_TIMECHANGE: {
-		Core::App().checkAutoLockIn(100);
-	} return false;
-
-	case WM_WTSSESSION_CHANGE: {
-		if (wParam == WTS_SESSION_LOGOFF || wParam == WTS_SESSION_LOCK) {
-			Core::App().setScreenIsLocked(true);
-		} else if (wParam == WTS_SESSION_LOGON || wParam == WTS_SESSION_UNLOCK) {
-			Core::App().setScreenIsLocked(false);
-		}
-	} return false;
-
-	case WM_DESTROY: {
-		App::quit();
-	} return false;
-
-	case WM_ACTIVATE: {
-		if (LOWORD(wParam) != WA_INACTIVE) {
-			_window->shadowsActivate();
-		} else {
-			_window->shadowsDeactivate();
-		}
-	} return false;
-
-	case WM_SIZE: {
-		if (wParam == SIZE_MAXIMIZED || wParam == SIZE_RESTORED || wParam == SIZE_MINIMIZED) {
-			if (wParam == SIZE_RESTORED && _window->windowState() == Qt::WindowNoState) {
-				_window->positionUpdated();
-			}
-		}
-	} return false;
-
-	case WM_MOVE: {
-		_window->positionUpdated();
-	} return false;
-
-	case WM_SETTINGCHANGE: {
-		Core::App().settings().setSystemDarkMode(Platform::IsDarkMode());
-	} return false;
-
-	}
-	return false;
-}
-
-} // namespace Platform
diff --git a/Telegram/SourceFiles/platform/win/windows_event_filter.h b/Telegram/SourceFiles/platform/win/windows_event_filter.h
deleted file mode 100644
index c313f29cf..000000000
--- a/Telegram/SourceFiles/platform/win/windows_event_filter.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
-This file is part of Telegram Desktop,
-the official desktop application for the Telegram messaging service.
-
-For license and copyright information please follow this link:
-https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
-*/
-#pragma once
-
-#include "base/platform/win/base_windows_h.h"
-
-#include <QtCore/QAbstractNativeEventFilter>
-
-namespace Platform {
-
-class MainWindow;
-
-class EventFilter : public QAbstractNativeEventFilter {
-public:
-	bool nativeEventFilter(const QByteArray &eventType, void *message, long *result);
-	bool mainWindowEvent(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam, LRESULT *result);
-
-	static EventFilter *CreateInstance(not_null<MainWindow*> window);
-	static void Destroy();
-
-private:
-	explicit EventFilter(not_null<MainWindow*> window);
-
-	not_null<MainWindow*> _window;
-
-};
-
-} // namespace Platform
diff --git a/Telegram/SourceFiles/window/main_window.cpp b/Telegram/SourceFiles/window/main_window.cpp
index 73c49355b..25b0f0850 100644
--- a/Telegram/SourceFiles/window/main_window.cpp
+++ b/Telegram/SourceFiles/window/main_window.cpp
@@ -340,6 +340,14 @@ Main::Account &MainWindow::account() const {
 	return _controller->account();
 }
 
+PeerData *MainWindow::singlePeer() const {
+	return _controller->singlePeer();
+}
+
+bool MainWindow::isPrimary() const {
+	return _controller->isPrimary();
+}
+
 Window::SessionController *MainWindow::sessionController() const {
 	return _controller->sessionController();
 }
diff --git a/Telegram/SourceFiles/window/main_window.h b/Telegram/SourceFiles/window/main_window.h
index 99c30d392..50b73d4ee 100644
--- a/Telegram/SourceFiles/window/main_window.h
+++ b/Telegram/SourceFiles/window/main_window.h
@@ -62,6 +62,8 @@ public:
 	[[nodiscard]] Window::Controller &controller() const {
 		return *_controller;
 	}
+	[[nodiscard]] PeerData *singlePeer() const;
+	[[nodiscard]] bool isPrimary() const;
 	[[nodiscard]] Main::Account &account() const;
 	[[nodiscard]] Window::SessionController *sessionController() const;
 
diff --git a/Telegram/SourceFiles/window/window_controller.cpp b/Telegram/SourceFiles/window/window_controller.cpp
index f69b3ac7e..921e17958 100644
--- a/Telegram/SourceFiles/window/window_controller.cpp
+++ b/Telegram/SourceFiles/window/window_controller.cpp
@@ -63,7 +63,7 @@ Controller::~Controller() {
 }
 
 void Controller::showAccount(not_null<Main::Account*> account) {
-	Expects(!_singlePeer || &_singlePeer->account() == account);
+	Expects(isPrimary() || &_singlePeer->account() == account);
 
 	const auto prevSessionUniqueId = (_account && _account->sessionExists())
 		? _account->session().uniqueId()
diff --git a/Telegram/SourceFiles/window/window_controller.h b/Telegram/SourceFiles/window/window_controller.h
index ce83903bc..f6b8b8b60 100644
--- a/Telegram/SourceFiles/window/window_controller.h
+++ b/Telegram/SourceFiles/window/window_controller.h
@@ -32,6 +32,9 @@ public:
 
 	void showAccount(not_null<Main::Account*> account);
 	[[nodiscard]] PeerData *singlePeer() const;
+	[[nodiscard]] bool isPrimary() const {
+		return (singlePeer() == nullptr);
+	}
 
 	[[nodiscard]] not_null<::MainWindow*> widget() {
 		return &_widget;