ListView Scrollbar height

[fecub]

Is it possible to change the height of an ScrollBar in Listview?

ListView {
    id: listView1
    Layout.fillWidth: true
    Layout.fillHeight: true
    model: 200
    clip: true

   .
   .
   .

    ScrollBar.vertical: ScrollBar {
        active: true

        width: 20
        height: 50  // changing this value, does nothing !!!


        onActiveChanged: {
            console.log(availableHeight)
            if (!active)
                active = true
        }
    }
}

I have set the height, but the ScrollBar height does not change. But changing the value of the width, make it wider ?!?!?

Edit:
Is it also possible to change the radius of the ScrollBar to make it more rectangular?