Update icons when icon theme on Linux changes

Telegram/SourceFiles/core/application.cpp

@@ -100,6 +100,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtCore/QMimeDatabase>
 #include <QtGui/QGuiApplication>
 #include <QtGui/QScreen>
+#include <QtGui/QWindow>
 
 namespace Core {
 namespace {
@@ -676,6 +677,13 @@ bool Application::eventFilter(QObject *object, QEvent *e) {
 			}
 		}
 	} break;
+
+	case QEvent::ThemeChange: {
+		if (Platform::IsLinux() && object == QGuiApplication::allWindows().first()) {
+			Core::App().refreshApplicationIcon();
+			Core::App().tray().updateIconCounters();
+		}
+	} break;
 	}
 
 	return QObject::eventFilter(object, e);

Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp

@@ -400,6 +400,8 @@ OverlayWidget::OverlayWidget()
 			e->ignore();
 			close();
 			return base::EventFilterResult::Cancel;
+		} else if (type == QEvent::ThemeChange && Platform::IsLinux()) {
+			_window->setWindowIcon(Window::CreateIcon(_session));
 		}
 		return base::EventFilterResult::Continue;
 	});

Telegram/SourceFiles/platform/linux/main_window_linux.cpp

@@ -179,6 +179,12 @@ MainWindow::MainWindow(not_null<Window::Controller*> controller)
 }
 
 void MainWindow::initHook() {
+	events() | rpl::start_with_next([=](not_null<QEvent*> e) {
+		if (e->type() == QEvent::ThemeChange) {
+			updateWindowIcon();
+		}
+	}, lifetime());
+
 	base::install_event_filter(windowHandle(), [=](not_null<QEvent*> e) {
 		if (e->type() == QEvent::Expose) {
 			auto ee = static_cast<QExposeEvent*>(e.get());
@@ -221,12 +227,7 @@ void MainWindow::updateWindowIcon() {
 	const auto session = sessionController()
 		? &sessionController()->session()
 		: nullptr;
-	const auto supportIcon = session && session->supportMode();
-	if (supportIcon != _usingSupportIcon || _icon.isNull()) {
-		_icon = Window::CreateIcon(session);
-		_usingSupportIcon = supportIcon;
-	}
-	setWindowIcon(_icon);
+	setWindowIcon(Window::CreateIcon(session));
 }
 
 void MainWindow::updateUnityCounter() {

Telegram/SourceFiles/platform/linux/main_window_linux.h

@@ -60,9 +60,6 @@ private:
 	QAction *psMonospace = nullptr;
 	QAction *psClearFormat = nullptr;
 
-	QIcon _icon;
-	bool _usingSupportIcon = false;
-
 };
 
 [[nodiscard]] inline int32 ScreenNameChecksum(const QString &name) {