diff --git a/src/main.cpp b/src/main.cpp
index 2668e2f..23bffcd 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,158 +1,167 @@
 /*
  * Copyright (C) 1997 by Stephan Kulow <coolo@kde.org>
  * Copyright (C) 2019  Alexander Potashev <aspotashev@gmail.com>
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation; either version 2 of the License, or
  *   (at your option) any later version.
  *
  *   This program is distributed in the hope that it will be useful,
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *   GNU General Public License for more details.
  *
  *   You should have received a copy of the GNU General Public License along
  *   with this program; if not, write to the
  *      Free Software Foundation, Inc.
  *      51 Franklin Street, Fifth Floor
  *      Boston, MA  02110-1301  USA.
  *
  */
 
 #include <QApplication>
 #include <QCommandLineOption>
 #include <QCommandLineParser>
 #include <QDir>
 #include <QFile>
 #include <QFileInfo>
 #include <QPointer>
 #include <QStandardPaths>
 
 #include <KAboutData>
 #include <KDBusService>
 #include <KLocalizedString>
 
 #include "desktoplist.h"
 #include "ktimetracker-version.h"
 #include "ktt_debug.h"
 #include "mainwindow.h"
 #include "model/task.h"
 #include "timetrackerstorage.h"
 
 // Deliver the path/URL to the iCalendar file to be used
 QUrl getFileUrl(const QCommandLineParser &parser)
 {
     // Get first positional argument ("file")
     const QStringList args = parser.positionalArguments();
     QString customFile;
     if (!args.isEmpty()) {
         customFile = args[0];
     }
 
     if (!customFile.isEmpty()) {
         // customFile is given as parameter
 
         const QUrl url = QUrl::fromUserInput(customFile, QDir::currentPath(), QUrl::AssumeLocalFile);
         if (!url.isValid()) {
             qCWarning(KTT_LOG) << "Invalid URL: " << customFile;
         }
 
         return url;
     } else {
         // customFile is not given as parameter
         QString result = QString(QStandardPaths::locate(QStandardPaths::GenericDataLocation, "ktimetracker/ktimetracker.ics"));
         if (result.isEmpty()) {
             result = QStandardPaths::writableLocation(QStandardPaths::DataLocation) + QLatin1Char('/') + QStringLiteral("ktimetracker.ics");
 
             QFileInfo fileInfo(result);
             QDir().mkpath(fileInfo.absolutePath());
 
             QFile oldFile(QStandardPaths::locate(QStandardPaths::GenericDataLocation, "karm/karm.ics"));
             if (oldFile.exists()) {
                 oldFile.copy(result);
             }
         }
 
         return QUrl::fromLocalFile(result);
     }
 }
 
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
     Q_INIT_RESOURCE(ktimetracker);
 
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps, true);
+    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling, true);
+
+#ifdef Q_OS_WIN
+    // Force Breeze theme on Windows.
+    // Kate text editor does the same.
+    QApplication::setStyle(QStringLiteral("breeze"));
+#endif
+
     KLocalizedString::setApplicationDomain("ktimetracker");
 
     KAboutData aboutData(
         QStringLiteral("ktimetracker"),
         i18n("KTimeTracker"),
         QStringLiteral(KTIMETRACKER_VERSION_STRING),
         i18n("KDE Time tracker tool"),
         KAboutLicense::GPL_V2,
         i18n("Copyright © 1997-2019 KTimeTracker developers"),
         QString(),
         QStringLiteral("https://userbase.kde.org/KTimeTracker"));
 
     aboutData.addAuthor(i18nc("@info:credit", "Alexander Potashev"),
                         i18nc("@info:credit", "Current Maintainer (since 2019)"),
                         QStringLiteral("aspotashev@gmail.com"));
     aboutData.addAuthor(i18nc("@info:credit", "Thorsten Stärk"),
                         i18nc("@info:credit", "Maintainer (2006-2012)"),
                         QStringLiteral("kde@staerk.de"));
     aboutData.addAuthor(i18nc("@info:credit", "Mark Bucciarelli"),
                         i18nc("@info:credit", "Maintainer (2005-2006)"),
                         QStringLiteral("mark@hubcapconsulting.com"));
     aboutData.addAuthor(i18nc("@info:credit", "Jesper Pedersen"),
                         i18nc("@info:credit", "Maintainer (2000-2005)"),
                         QStringLiteral("blackie@kde.org"));
     aboutData.addAuthor(i18nc("@info:credit", "Sirtaj Singh Kang"),
                         i18nc("@info:credit", "Original Author"),
                         QStringLiteral("taj@kde.org"));
     aboutData.addAuthor(i18nc("@info:credit", "Mathias Soeken"),
                         i18nc("@info:credit", "Developer (in 2007)"),
                         QStringLiteral("msoeken@tzi.de"));
     aboutData.addAuthor(i18nc("@info:credit", "Kalle Dalheimer"),
                         i18nc("@info:credit", "Developer (1999-2000)"),
                         QStringLiteral("kalle@kde.org"));
     aboutData.addAuthor(i18nc("@info:credit", "Allen Winter"),
                         i18nc("@info:credit", "Developer"),
                         QStringLiteral("winter@kde.org"));
     aboutData.addAuthor(i18nc("@info:credit", "David Faure"),
                         i18nc("@info:credit", "Developer"),
                         QStringLiteral("faure@kde.org"));
     KAboutData::setApplicationData(aboutData);
     QApplication::setWindowIcon(QIcon::fromTheme(QStringLiteral("ktimetracker")));
 
     QCommandLineParser parser;
     aboutData.setupCommandLine(&parser);
 
     parser.addPositionalArgument(QStringLiteral("url"), i18nc("@info:shell", "Path or URL to iCalendar file to open."));
 
     parser.process(app);
     aboutData.processCommandLine(&parser);
 
     KDBusService dbusService(KDBusService::Unique);
 
     const QUrl &url = getFileUrl(parser);
 
 //        if (!KUniqueApplication::start()) {
 //            qCDebug(KTT_LOG) << "Other instance is already running, exiting!";
 //            return 0;
 //        }
 //        KUniqueApplication myApp;
     QPointer<MainWindow> mainWindow = new MainWindow(url);
     mainWindow->show();
 
     if (app.isSessionRestored()) {
         const QString className = KXmlGuiWindow::classNameOfToplevel(1);
         if (className == QLatin1String("MainWindow")) {
             mainWindow->restore(1);
         } else {
             qCWarning(KTT_LOG) << "Unknown class " << className << " in session saved data!";
         }
     }
 
     return app.exec();
 }