I am working with Qt 6.9.3 and customizing a ScrollBar using the QtQuick.Controls.Basic style. I have encountered an issue where the ScrollBar.AsNeeded policy does not work as expected when attached to a ListView.When the ListView is completely empty (or content fits within bounds), the scroll handle/thumb correctly hides, but the custom background track remains permanently visible on the screen. If I switch back to the default QtQuick.Controls style without customization, the AsNeeded policy works perfectly.

Here is the custom ScrollBar implementation I am using in a standalone file:

// CustomScrollBar.qml
import QtQuick
import QtQuick.Controls.Basic

ScrollBar {
    id: control
    policy: ScrollBar.AsNeeded
    minimumSize: 0.1
    hoverEnabled: false

    contentItem: Rectangle {
        implicitWidth: 10
        implicitHeight: 10
        color: control.pressed ? "#444" : "#888"
        // Handle correctly tracks active/size states
        visible: control.policy === ScrollBar.AlwaysOn || (control.active && control.size < 1.0)
    }

    background: Rectangle {
        implicitWidth: control.implicitWidth
        color: "#E0E0E0"
        // This background remains visible even when ListView is empty (control.size == 1.0)
    }
}

And how it is attached:

ListView {
    id: listView
    Layout.fillHeight: true
    Layout.fillWidth: true
    clip: true
    model: 0 // Empty for testing

    ScrollBar.vertical: CustomScrollBar {
        anchors.right: listView.right
    }
}

Is there a specific internal property or visibility binding for the background item in the Basic style template that I need to manually handle to make it respect the AsNeeded policy when the view has no overflow?

Thanks for your help!