BUG: Tree-Like Grid

[quagliarellamichel]

In remote source mode, upon clicking expand row
correctly displays the grouped rows to me,
but when I click collapse row it reloads the same rows again duplicating them

$('#grid').w2grid({
                title: '@ViewData["Title"]',
                name: 'grid',
                method: 'POST',
                dataType: 'RESTFULLJSON',
                url: "@Url.Action("GetData")",
                selectType: 'row',
                multiSearch: true,
                markSearch: false,
                setting: {
                    arnNoPhrase: true,
                    currencyPrecision: 2,
                    dateFormat: "dd/mm/yyyy"
                },
                searchLogic: "AND",
                searches: [
                    { field: 'User', label: 'User', type: 'text' },
                    { field: 'Number', label: 'Number', type: 'text' },
                    { field: 'NSpc', label: 'N° Spc', type: 'text' },
                    { field: 'Mode', label: 'Mode', type: 'text' },
                    { field: 'Note', label: 'Note', type: 'text' },
                    { field: 'Engineer', label: 'Engineer', type: 'text' },
                    { field: 'Itemid', label: 'Tendigit', type: 'text' },
                    { field: 'Pn', label: 'PN', type: 'text' },
                    { field: 'Customer', label: 'Customer', type: 'text' },
                    { field: 'FileName', label: 'FileName', type: 'text' },
                ],


                show: {
                    toolbar: true,
                    footer: true,
                    expandColumn: true,
                },

                columns: @Html.Raw(ViewData["w2ColumnsGrid"]),

                
            });