ChartView buggy when specifying `plotArea`

Developer123

ChartView is very buggy by nature, but when you speficy plotArea attribute the buggyness gets over the charts.

Exemple code:

import QtQuick 2.15
import QtCharts 2.15
import QtGraphicalEffects 1.15
import QtQuick.Controls 2.15

Rectangle {
    width: 500
    height: 300
    ChartView{
      id: chart_component
      anchors.fill: parent
      backgroundColor: "#000044"

      plotArea: Qt.rect(40, 40, chart_component.width-60, chart_component.height-60)

      // X Axis
      ValueAxis {
          id: valueAxisX
          titleVisible: false
          visible : true
          min: 0
          max: 10
          tickCount: 10
          labelFormat: "%.2f"
      }

      // Y Axis
      ValueAxis {
          id: valueAxisY
          min: 0.0
          max: 10.0
          tickCount: 5
          labelFormat: "%.2f"
      }
      LineSeries {
          id: defaultSeries
          name: "default"
          color: "green"
          axisX: valueAxisX
          axisY: valueAxisY

          XYPoint { x: 0; y: 0 }
          XYPoint { x: 1.1; y: 2.1 }
          XYPoint { x: 1.9; y: 3.3 }
          XYPoint { x: 2.1; y: 2.1 }
          XYPoint { x: 2.9; y: 4.9 }
          XYPoint { x: 3.4; y: 3.0 }
          XYPoint { x: 4.1; y: 3.3 }
      }

      Button {
          id: button
          x: 382
          y: 18
          text: qsTr("ZOOM")
          onClicked: {
              chart_component.zoomIn()
          }
      }


 }
}

/*##^##
Designer {
    D{i:0;formeditorZoom:2}D{i:2}D{i:3}D{i:4}D{i:12}D{i:1}
}
##^##*/

As you can see, the backgroundColor: "#000044" is not being rendered, instead it shows the background from the Rectangle, which is white:

As a side effect, on every re-render, the last frame is not earased. In this case, if I zoom into the Graph by clicking on the button, everything gets blended:

Any ideas how to solve this?