Custom SubWindow in QQuickWindow

[Cute3d]

Hi,

I want to display a custom subwindow in my qquickwindow. I want to render my own content into this subwindow.
The reason why I don't render directly into the quickwindow is, that it "overdraws" the toolbar and buttons.

Window {
    id: myMainWindow
    visible: true;
    width: 1920
    height: 1080

    MultiPointTouchArea{
        id: touchAreaOne;
        anchors.fill: parent
        mouseEnabled: true
        touchPoints: [
            TouchPoint{ id: touch1},
            TouchPoint{ id: touch2}
        ]
        onTouchUpdated: {
            console.log("touch");
        }
    }
    ToolBar {
        id: tool_bar
        z: 20 
        visible : true

    }
    Rectangle{
        id: subWindow
        color: "transparent"
        anchors.fill: parent
        CustomWindow {

        }
    }
}

So I tried it like the example above. But than I can see only the rectangle and not the window.
I tried to implement the customwindow as qwindow and as qquickwindow. Although I would prefer the Qwindow.

Does anyone has an idea how it could work