MessageDialog is triggering handler twice

import QtQuick 2.12
import QtQuick.Dialogs 1.3
import QtQuick.Controls 1.2
MessageDialog {
 id: root
 icon: StandardIcon.Information
 title: qsTr("Delete content")
 text: qsTr("<p>You are about to delete file.</p>" +
 "<p>Tap 'OK' when you are ready to proceed.</p>")
 standardButtons: StandardButton.Cancel | StandardButton.Ok
Component.onCompleted: {
console.log("test onCompleted")
 open()
 }
onAccepted: {console.log("test onAccepted")}
 onRejected: {console.log("test onRejected")}
}

qml: test onCompleted
qml: test onAccepted
qml: test onAccepted
qml: test onCompleted
qml: test onRejected
qml: test onRejected