c++ side
--------------------------------------------
bool DataModel::moveRows(const QModelIndex &sourceParent, int sourceRow, int count, const QModelIndex &destinationParent, int destinationChild)
{    
    if (areIndexesSame(sourceParent, destinationParent)) {
        if (sourceRow == destinationChild) {
            qDebug() << "sourceRow == destinationChild in case when parent is same @" << Q_FUNC_INFO;
            return true;
        }
        if (sourceRow < destinationChild) {
            beginMoveRows(sourceParent, sourceRow, sourceRow + count - 1, sourceParent, destinationChild + count);
        } else {
            beginMoveRows(sourceParent, sourceRow, sourceRow + count - 1, sourceParent, destinationChild);
        }
    } else {
        beginMoveRows(sourceParent, sourceRow, sourceRow + count - 1, destinationParent, destinationChild + 1);
    }

    // checking offspring
    const QModelIndex & sourceIndex = index(sourceRow, 0, sourceParent);
    const QModelIndex & destinationIndex = index(destinationChild, 0, destinationParent);
    bool ok = checkIfOffspring(destinationIndex, sourceIndex);
    if (ok) {
        qDebug() << " destination is parent of source " << Q_FUNC_INFO;
        return false;
    }
    const PersistantStorageSyncWorker * worker = getPersistantStorageWorker();
    ok = worker->moveRows(sourceParent, sourceRow, count, destinationParent, destinationChild);
    if (!ok)
        return false;
    QAbstractItemModel::endMoveRows();
    //beginResetModel(); //FIXME because of bug https://bugreports.qt.io/browse/QTBUG-55864 I have to resetModel to update indexes in treeview.
    //endResetModel(); //TODO check if it is fixed as this bug was closed
    return true;
}

---------------------------
QML side where I initiate move actually
---------------------------

//where indx is bind to styleData.index (here is the bug probably)

Rectangle {
            id: moveTaskButton
            anchors.left: parent.left
            anchors.bottom: parent.bottom
            height: editor.height * 0.3
            width: height
            visible: open
            border.width: 1 * dp
            Text {
                id: textOfMoveTaskButton
                anchors.centerIn: parent
                text: treeModel.isSourceSet() ? "paste" : "move"
                font.pointSize: moveTaskButton.height * 0.5 > 1 ? moveTaskButton.height * 0.15 : 1
                onVisibleChanged: {
                    text = treeModel.isSourceSet() ? "paste" : "move"
                }
            }
            MouseArea {
                anchors.fill: parent
                onClicked: {
                    if (treeModel.isSourceSet()) {
                        treeModel.setTargetToMove(indx)
                        textOfMoveTaskButton.text = "move"
                        //open = false
                    } else {
                        treeModel.setSourceToMove(indx)
                        textOfMoveTaskButton.text = "paste"
                    }
                }
            }
        }