QML StackView: push: nothing to push

Question

I have one listView, on mouseArea after clicking on listview elements should append in Rectangle.but first elements appends but later saying that noting to push

QML debugging is enabled. Only use this in a safe environment.
qml: Layout
qml: Layout_send_id
qrc:/main.qml:62:9: QML StackView: push: nothing to push

Images for references

I want continue appending but it is replacing and show error as nothing to push

import QtQuick.Controls.Styles 1.4
import QtQuick.Controls.Material 2.4
import QtQuick.Layouts 1.3
import QtQuick.Controls 1.4
import QtQuick 2.4
import QtQuick.Controls 2.12

ApplicationWindow {

    id:mainWindow
    visible: true
    width: 640
    height: 480
    title: qsTr("Scroll vertical horizontal")

    Rectangle{

        id:selectedItem
        x:parent.width*0.2
        y:parent.height*0.05
        border.color: "black"
        width: parent.width*0.3
        height: parent.height*0.25

        StackView{
            id:layoutStack
        }
    }
    
    StackLayout{
        id:stackModel
    }


    Item{
        id:element
        Rectangle{

        width: val*10
        height: 20
        border.color: "green"

            Text {
                id: input
            }
        }
    }

    ListModel{
        id:listModel
        ListElement{
            name : "Layout"
        }
        ListElement{
            name : "Layout_send_id"
        }
        ListElement{
            name : "Layout_received_id"
        }
    }

    property var val

    ListView{
        id:listView
        x:parent.width*0.2
        y:parent.height*0.35
        model: listModel
        width: 200
        height: 250

        delegate: Rectangle{
            id:recta
            width: parent.width
            height: 20
            border.color: "brown"
            Text {
                id: name
                text: model.name
            }

            MouseArea{
                id:clickArea
                anchors.fill: parent
                onClicked: {
                    val = (model.name).length
                    console.log(model.name)
                    input.text =model.name
                    layoutStack.push(element)
                }
            }
        }

    }
}