Not work when Flow and MouseArea in a ScrollView

[kacapeng]

no MouseArea:

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.0


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


    ScrollView{
        anchors.fill: parent

        Flow{
            width: parent.width
            Rectangle{
                width: 300
                height: 300
                color: "red"
            }
            Rectangle{
                width: 300
                height: 300
                color: "blue"
            }
            Rectangle{
                width: 300
                height: 300
                color: "pink"

                MouseArea{
                    anchors.fill: parent
                    onClicked:{
                        parent.color =  Qt.rgba(Math.random(), Math.random(), Math.random())
                    }

                }
            }

        }
    }
}

Add a MouseArea:

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.0


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


    ScrollView{
        anchors.fill: parent
        MouseArea{
            anchors.fill: parent
            onClicked: {
                root.color = Qt.rgba(Math.random(), Math.random(), Math.random())
            }
        }
        Flow{
            width: parent.width
            Rectangle{
                width: 300
                height: 300
                color: "red"
            }
            Rectangle{
                width: 300
                height: 300
                color: "blue"
            }
            Rectangle{
                width: 300
                height: 300
                color: "pink"

                MouseArea{
                    anchors.fill: parent
                    onClicked:{
                        parent.color =  Qt.rgba(Math.random(), Math.random(), Math.random())
                    }

                }
            }

        }
    }
}

How do I let ScrollView accept mouse events?