Qt Quick2 Material Dark Theme looks buggy/unreadable - qt

Question

I applied Material Dark Theme on my application as recommended on this question:
main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQuickStyle>
#include <QDebug>
int main(int argc, char *argv[])
{
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
#endif
qputenv("QT_QUICK_CONTROLS_STYLE", QByteArray("Material"));
qputenv("QT_QUICK_CONTROLS_MATERIAL_THEME", QByteArray("Dark"));
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
const QUrl url(QStringLiteral("qrc:/main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
&app, [url](QObject *obj, const QUrl &objUrl) {
if (!obj && url == objUrl)
QCoreApplication::exit(-1);
}, Qt::QueuedConnection);
engine.load(url);
return app.exec();
}
And my main.qml:
import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.5
Window {
width: 640
height: 480
visible: true
title: qsTr("Hello World")
Button {
id: button
x: 145
y: 70
width: 151
height: 90
text: qsTr("Button")
}
RoundButton {
id: roundButton
x: 401
y: 120
text: "+"
}
CheckBox {
id: checkBox
x: 157
y: 297
text: qsTr("Check Box")
}
Slider {
id: slider
x: 345
y: 232
value: 0.5
}
DelayButton {
id: delayButton
x: 377
y: 344
text: qsTr("Delay Button")
}
Switch {
id: switch1
x: 151
y: 409
text: qsTr("Switch")
}
}
While default material works as expected, if I change to material dark it looks like this:
Material dark looks buggy:
I am pretty sure it shouldn't look like this. Did I miss to install something or do I need to import something additionally?
Using qtcreator on Windows, qml objects are just random unchanged controls.

Answer 1

That should work with the Window from Qt Quick. Please create a bug report for that. Using ApplicationWindow does work though.