diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index 593d6f4a0b..53e01dd106 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/application.h"
 
 #include "data/data_abstract_structure.h"
+#include "data/data_channel.h"
 #include "data/data_forum.h"
 #include "data/data_message_reactions.h"
 #include "data/data_session.h"
@@ -1377,8 +1378,9 @@ Window::Controller *Application::windowForShowingHistory(
 
 Window::Controller *Application::windowForShowingForum(
 		not_null<Data::Forum*> forum) const {
+	const auto tabs = forum->channel()->useSubsectionTabs();
 	const auto id = Window::SeparateId(
-		Window::SeparateType::Forum,
+		tabs ? Window::SeparateType::Chat : Window::SeparateType::Forum,
 		forum->history());
 	if (const auto separate = separateWindowFor(id)) {
 		return separate;
@@ -1386,9 +1388,15 @@ Window::Controller *Application::windowForShowingForum(
 	auto result = (Window::Controller*)nullptr;
 	enumerateWindows([&](not_null<Window::Controller*> window) {
 		if (const auto controller = window->sessionController()) {
-			const auto current = controller->shownForum().current();
-			if (forum == current) {
-				result = window;
+			if (tabs) {
+				if (controller->windowId() == id) {
+					result = window;
+				}
+			} else {
+				const auto current = controller->shownForum().current();
+				if (forum == current) {
+					result = window;
+				}
 			}
 		}
 	});
diff --git a/Telegram/SourceFiles/dialogs/dialogs_widget.cpp b/Telegram/SourceFiles/dialogs/dialogs_widget.cpp
index 06b1ac9294..6b6227b9a3 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_widget.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_widget.cpp
@@ -911,8 +911,10 @@ void Widget::chosenRow(const ChosenRow &row) {
 		if (controller()->shownForum().current() == forum) {
 			controller()->closeForum();
 		} else if (row.newWindow) {
-			controller()->showInNewWindow(
-				Window::SeparateId(Window::SeparateType::Forum, history));
+			const auto type = forum->channel()->useSubsectionTabs()
+				? Window::SeparateType::Chat
+				: Window::SeparateType::Forum;
+			controller()->showInNewWindow(Window::SeparateId(type, history));
 		} else {
 			controller()->showForum(
 				forum,
diff --git a/Telegram/SourceFiles/window/notifications_manager.cpp b/Telegram/SourceFiles/window/notifications_manager.cpp
index f34c3a1084..0038a41783 100644
--- a/Telegram/SourceFiles/window/notifications_manager.cpp
+++ b/Telegram/SourceFiles/window/notifications_manager.cpp
@@ -1176,9 +1176,11 @@ Window::SessionController *Manager::openNotificationMessage(
 		}
 	});
 
-	const auto separateId = topic
-		? Window::SeparateId(Window::SeparateType::Forum, history)
-		: Window::SeparateId(history->peer);
+	const auto separateId = !topic
+		? Window::SeparateId(history->peer)
+		: history->peer->asChannel()->useSubsectionTabs()
+		? Window::SeparateId(Window::SeparateType::Chat, topic)
+		: Window::SeparateId(Window::SeparateType::Forum, history);
 	const auto separate = Core::App().separateWindowFor(separateId);
 	const auto itemId = openExactlyMessage ? messageId : ShowAtUnreadMsgId;
 	if (openSeparated && !separate && !topic) {
diff --git a/Telegram/SourceFiles/window/window_peer_menu.cpp b/Telegram/SourceFiles/window/window_peer_menu.cpp
index 0f48fb48f7..477b1b6707 100644
--- a/Telegram/SourceFiles/window/window_peer_menu.cpp
+++ b/Telegram/SourceFiles/window/window_peer_menu.cpp
@@ -669,7 +669,7 @@ void Filler::addNewWindow() {
 			if (const auto sublist = weak.get()) {
 				controller->showInNewWindow(SeparateId(
 					SeparateType::SavedSublist,
-					sublist->owner().history(sublist->sublistPeer())));
+					sublist));
 			}
 		}, &st::menuIconNewWindow);
 		AddSeparatorAndShiftUp(_addAction);
@@ -690,7 +690,9 @@ void Filler::addNewWindow() {
 	_addAction(tr::lng_context_new_window(tr::now), [=] {
 		Ui::PreventDelayedActivation();
 		if (const auto strong = weak.get()) {
-			const auto forum = !strong->asTopic() && peer->isForum();
+			const auto forum = !strong->asTopic()
+				&& peer->isForum()
+				&& !peer->asChannel()->useSubsectionTabs();
 			controller->showInNewWindow(SeparateId(
 				forum ? SeparateType::Forum : SeparateType::Chat,
 				strong));
@@ -2472,7 +2474,7 @@ QPointer<Ui::BoxContent> ShowForwardMessagesBox(
 				return true;
 			}
 			const auto id = SeparateId(
-				(peer->isForum()
+				((peer->isForum() && !peer->asChannel()->useSubsectionTabs())
 					? SeparateType::Forum
 					: SeparateType::Chat),
 				thread);
diff --git a/Telegram/SourceFiles/window/window_separate_id.cpp b/Telegram/SourceFiles/window/window_separate_id.cpp
index c6b0f0da62..f6ed9155fd 100644
--- a/Telegram/SourceFiles/window/window_separate_id.cpp
+++ b/Telegram/SourceFiles/window/window_separate_id.cpp
@@ -31,14 +31,10 @@ SeparateId::SeparateId(SeparateType type, not_null<Main::Session*> session)
 , account(&session->account()) {
 }
 
-SeparateId::SeparateId(
-	SeparateType type,
-	not_null<Data::Thread*> thread,
-	ChannelData *parentChat)
+SeparateId::SeparateId(SeparateType type, not_null<Data::Thread*> thread)
 : type(type)
 , account(&thread->session().account())
-, thread(thread)
-, parentChat((type == SeparateType::SavedSublist) ? parentChat : nullptr) {
+, thread(thread) {
 }
 
 SeparateId::SeparateId(not_null<Data::Thread*> thread)
@@ -77,12 +73,9 @@ Data::Folder *SeparateId::folder() const {
 }
 
 Data::SavedSublist *SeparateId::sublist() const {
-	const auto monoforum = parentChat ? parentChat->monoforum() : nullptr;
 	return (type != SeparateType::SavedSublist)
 		? nullptr
-		: monoforum
-		? monoforum->sublist(thread->peer()).get()
-		: thread->owner().savedMessages().sublist(thread->peer()).get();
+		: thread->asSublist();
 }
 
 bool SeparateId::hasChatsList() const {
diff --git a/Telegram/SourceFiles/window/window_separate_id.h b/Telegram/SourceFiles/window/window_separate_id.h
index e36e8c2a98..dbc79397a5 100644
--- a/Telegram/SourceFiles/window/window_separate_id.h
+++ b/Telegram/SourceFiles/window/window_separate_id.h
@@ -46,10 +46,7 @@ struct SeparateId {
 	SeparateId(std::nullptr_t);
 	SeparateId(not_null<Main::Account*> account);
 	SeparateId(SeparateType type, not_null<Main::Session*> session);
-	SeparateId(
-		SeparateType type,
-		not_null<Data::Thread*> thread,
-		ChannelData *parentChat = nullptr);
+	SeparateId(SeparateType type, not_null<Data::Thread*> thread);
 	SeparateId(not_null<Data::Thread*> thread);
 	SeparateId(not_null<PeerData*> peer);
 	SeparateId(
@@ -60,7 +57,6 @@ struct SeparateId {
 	Storage::SharedMediaType sharedMediaType = {};
 	Main::Account *account = nullptr;
 	Data::Thread *thread = nullptr; // For types except Main and Archive.
-	ChannelData *parentChat = nullptr;
 	[[nodiscard]] bool valid() const {
 		return account != nullptr;
 	}
diff --git a/Telegram/SourceFiles/window/window_session_controller.cpp b/Telegram/SourceFiles/window/window_session_controller.cpp
index 523777e882..1fe5d152cc 100644
--- a/Telegram/SourceFiles/window/window_session_controller.cpp
+++ b/Telegram/SourceFiles/window/window_session_controller.cpp
@@ -1877,8 +1877,7 @@ void SessionController::showForum(
 		const SectionShow &params) {
 	if (showForumInDifferentWindow(forum, params)) {
 		return;
-	} else if (HistoryView::SubsectionTabs::UsedFor(
-			forum->owner().history(forum->channel()))) {
+	} else if (forum->channel()->useSubsectionTabs()) {
 		showPeerHistory(forum->channel(), params);
 		return;
 	}