Here is a complete listing of the example source file.
import QtQuick 2.11
import QtQuick.Controls 2.1
import QtQuick.Layouts 1.3
 
 
ElementSettings {
    element: fan
 
    property CentrifugalFan fan
 
 
    GroupBox {
        title: qsTr("Custom properties")
 
        Layout.fillWidth: true
 
        GridLayout {
            columns: 2
 
            Label {
                text: qsTr("Mirror:")
            }
 
            CheckBox {
                checked: fan.mirror
 
                onCheckedChanged: fan.mirror = checked
            }
 
            Label {
                text: qsTr("RPM:")
            }
 
            Slider {
                from: 0
                to: 120
 
                value: fan.implicitRpm
 
                onValueChanged: fan.implicitRpm = value
            }
        }
    }
}