Modal functionality dissapear after "find" or "reset" clicked

Question

Hi guys. I'm having an issue with modal search. Modal pop up shows ok, but after "reset" or "find" is clicked the modal functionality disspear and although search box remains active you can click into jqGrid. Don't know if is a problem with the overlay. Ideas?

jQuery("#listNoticias").jqGrid({
            url: '<%= Url.Action("ObtenerDatosGrid") %>',
            datatype: 'json',
            mtype: 'GET',
            loadui: 'block',
            multiselect: false,
            colNames: ['Id', 'Creada', 'Titulo', 'Opciones'],
            colModel: [
              { index: 'Id', hidden: true, search: false },
              { index: 'Creada', width: 50, align: 'left', searchoptions: { dataInit: datePick, sopt: ['le', 'ge', 'eq']} },
              { index: 'Titulo', width: 150, align: 'left', searchoptions: { sopt: ['cn']} },
              { index: 'Opciones', width: 50, formatter: formatOpciones, align: 'center', sortable: false, search: false }
            ],

            pager: jQuery('#pagerNoticias'),
            rowNum: 8,
            rowList: [8, 15, 20],
            sortname: 'Creada',
            sortorder: 'desc',
            viewrecords: true,
            imgpath: '/content/cupertino/images',
            height: 240,
            width: 867,
            hidegrid: false
            //});
        }).navGrid(jQuery('#pagerNoticias'), { search: true, edit: false, add: false, del: false, searchtext: "Buscar" },
        {}, //  default settings for edit
        {}, //  default settings for add
        {},  // delete instead that del:false we need this
        { closeAfterSearch: false, drag: true, closeOnEscape: true }, // search options
        {} /* view parameters*/

        );