Flickering in QML SwipeView - c++

Question

Summary
QML Swipeview has problems updating when model of repeater is reset. The Qt version is 5.12.
Description
Following the doc in (https://doc.qt.io/qt-5/qml-qtquick-controls2-swipeview.html) a SwipeView is implemented. Difference with the example stated in the link, is that no Loader is used. The model of the Repeater is injected by the parent view in form of a QAbstractListModel.
When the viewModel is reset, the SwipeView has problems to update. It causes several repaints of the first page. For the user this appears as if the views is flickering. In the following the QML file and update function of the QAbstractListModel is described.
QML File:
Item {
id: root
/**
Set the model (is of type QAbstractListModel
**/
property var viewModel
height: 30 * Screen.pixelDensity
width: 60 * Screen.pixelDensity
Rectangle {
id: wrapper
anchors.fill: parent
color: "grey"
SwipeView {
id: swipe
clip: true
anchors.fill: parent
Repeater {
model: root.viewModel
Rectangle {
width: 20
height: 20
border.color: "black"
border.width: 1
Text {
text: index
}
}
}
}
}
}
Update Function:
void DerivedQAbstractList::setPages(const std::vector<Pages> &pages)
{
beginResetModel();
// create internal data structure
endResetModel();
}
Observations:
Update problem does not appear when the QAbstractList model is initially empty.
Using the Repeater without a SwipeView works fine (e.g. Column {Repeater {...}}
Do you have any ideas what could be the problem. Or give me an alternative approach to have a swiping view with dynamical model?
Edit 1.0. Using a Instantiator
As asked in the comment, we tried to replace the Repeater with an Instantiator. We can see from the console log, that the components are created. However they do not appear on the screen. What do we miss?
Rectangle {
id: wrapper
anchors.fill: parent
color: "grey"
SwipeView {
id: swipe
clip: true
anchors.fill: parent
Instantiator {
model: root.viewModel
delegate: Rectangle {
Component.onCompleted: console.log("Created")
width: 20
height: 20
border.color: "black"
border.width: 1
Text {
text: index
}
}
}
}
}