Foreground property for Button in QML

I am trying to change the foreground visibility of a QML button. Based on the content i read from internet and QML documentations, i have developed the below example.

import QtQuick 2.15
import QtQuick.Window 2.2
import QtQuick.Controls 2.2
import QtQuick.Layouts 1.3 
Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")     
Button {
        id: myButton
        text: "Click Me"
        foreground: ColumnLayout{
            anchors.fill: parent
            visible: false
            Rectangle {
                id:rect1
                Text{
                    text: "Rect1"
                }
            }
            Rectangle{
                id:rect2
                Text{
                    text: "Rect2"
                }
            }
        }         
onClicked: {
            myButton.foreground.visible = !myButton.foreground.visible; // toggle visibility of foreground
        }
    }
}

When i am trying to exevute i am facing the following error.

"cannot assign to non-existent property foreground", the versions that i am importing are QtQuick 2.15 & QtQuick.Controls.2.15

Can someone help on achieving the above expectation.

Thanks in advance !!

You can give a try using contentItem as below

import QtQuick 2.9
import QtQuick.Window 2.2
import QtQuick.Controls 2.2
import QtQuick.Layouts 1.3

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Button {
        id: myButton
        text: "Click Me"
        implicitWidth: 162
        implicitHeight: 162
        contentItem:ColumnLayout{
            id: colLayout
            visible: false
            Rectangle{
                width: 50
                height: 50
                color: "blue"
                Text{
                    text:qsTr("Rect1")
                }
            }
            Rectangle{
                width: 50
                height: 50
                color: "blue"
                Text{
                    text:qsTr("Rect2")
                }
            }
        }
        onClicked: {
            colLayout.visible = !colLayout.visible; // toggle visibility of foreground
        }
    }
}