QtQuick2 dragging frameless window

I done it as follow:

Window {
    id: window
    height: 400
    width: 250
    x: (Screen.width - width)/2     //<---start position of window
    y: (Screen.height - height)/2   //<-┘
    color: "transparent"
    flags: Qt.MSWindowsFixedSizeDialogHint | Qt.FramelessWindowHint

    MouseArea {
        anchors.fill: parent
        property point lastMousePos: Qt.point(0, 0)
        onPressed: { lastMousePos = Qt.point(mouseX, mouseY); }
        onMouseXChanged: window.x += (mouseX - lastMousePos.x)
        onMouseYChanged: window.y += (mouseY - lastMousePos.y)
    }

    Item {
        id: myFirstPage
        anchors.fill: parent
        anchors.topMargin: 50
        //...
        //This item can have some mouse area
    }
}

Now you can move window using dragging top 50 pixels or any where that is not under any MouseArea.

Also to resemble Windows behaviour of maximizing window when dragging it above vertical edge of the screen:

MouseArea {
    anchors.fill: parent;
    property variant clickPos: "1,1"

    onPressed: {
        clickPos = Qt.point(mouse.x,mouse.y)
    }

    onPositionChanged: {
        var delta = Qt.point(mouse.x-clickPos.x, mouse.y-clickPos.y)
        var new_x = mainWindow.x + delta.x
        var new_y = mainWindow.y + delta.y
        if (new_y <= 0)
            mainWindow.visibility = Window.Maximized
        else
        {
            if (mainWindow.visibility === Window.Maximized)
                mainWindow.visibility = Window.Windowed
            mainWindow.x = new_x
            mainWindow.y = new_y
        }
    }
}

In my project I do:

property variant clickPos: "1,1"

onPressed: {
    clickPos  = Qt.point(mouse.x,mouse.y)
}

onPositionChanged: {
    var delta = Qt.point(mouse.x-clickPos.x, mouse.y-clickPos.y)
    rootWindow.x += delta.x;
    rootWindow.y += delta.y;
}

In MouseArea.

A rather complete example:

import QtQuick 2.14
import QtQuick.Controls 2.14

ApplicationWindow {
    visible: true
    width: 200
    height: 200
    flags: Qt.FramelessWindowHint
    MouseArea {
        anchors.fill: parent
        onPressed: { pos = Qt.point(mouse.x, mouse.y) }
        onPositionChanged: {
            var diff = Qt.point(mouse.x - pos.x, mouse.y - pos.y)
            ApplicationWindow.window.x += diff.x
            ApplicationWindow.window.y += diff.y
        }
        property point pos
    }
}