Set Attributes before constructing the Application
QtWebEngine::initialize is the same as setting Qt::AA_ShareOpenGLContexts before constructing a QGuiApplication (https://doc.qt.io/qt-5/qtwebengine.html#initialize) and the current way causes the following warning:
QtWebEngine::initialize() called with QCoreApplication object already created and should be call before. This is depreciated and may fail in the future. Attribute Qt::AA_ShareOpenGLContexts must be set before QCoreApplication is created.
I moved AA_UseHighDpiPixmaps up as well, as other Applications like Kate and Ark doing it as well in this place. And in this way both setAttributes are next to each other.