What is the difference between QML Rectangle and Window?

xalam

I create a new Qt Quick application with default basic code. Now if I only replace 'Window' below with`Rectangle', this application never runs..more accurately it runs in the background but GUI never shows up.

What really is the difference between Window or Rectangle? Why does the application behaviors changes so much that it doesn't even run properly?

@import QtQuick 2.3
import QtQuick.Window 2.2

Window {
visible: true
width: 360
height: 360

MouseArea {
    anchors.fill: parent
    onClicked: {
        Qt.quit();
    }
}

Text {
    text: qsTr("Hello World")
    anchors.centerIn: parent
}

}@

The main.cpp file is here

@#include <QGuiApplication>
#include <QQmlApplicationEngine>

int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);

QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

return app.exec&#40;&#41;;

}@