Missing authorization headers in flat-form mode

We are using flexmonster inside angular application to connect to mongodb connector. For authentication client provides Authorization Bearer in header of request, but the problem is that this Authorization header is not sent when flexmonster mode is changing - apply button on options dialog will not send request headers:
This is how we include flexmonster in demo app:
    <script type="text/javascript">
        var pivot = new Flexmonster({
            container: "#pivot",
            componentFolder: "https://cdn.flexmonster.com/",
            height: 600,
            toolbar: true,
            report: {
                "dataSource": {
                    "type": "api",
                    "url": "http://localhost:9204/mongo",
                    "index": "characteristic_history",
                    "requestHeaders": {
                        'Authorization': 'Bearer TEST_TOKEN_WHICH_IS_NOT_SENT_IN_FLAT_MODE'
                },
                }
            },
             licenseKey: "Z7EI-XB9J6V-07676E-0E1B2A"
        });
    </script>
 
Looks like when report has been changed via options dialog - compact to flat and vise versa - Authorization headers are lost. 
What should we do that we get Authorization Bearer to be sent in flet-form mode to server?