jQuery Grid Plugin - jqGrid

I created single column treeview using code below. Gray horizontal lines appear between rows and there is gray border around grid. How to remove those lines so it looks like normal treeview ?

            $("#west-grid").jqGrid({
                url: '<%= ResolveUrl("~/Store/GridData")%>',
                datatype: "json",
                mtype: "POST",
                height: "auto",
                loadui: "disable",
                treeGridModel: "adjacency",
                colModel: [
                        { name: "id", width: 1, hidden: true, key: true },
                        { name: "menu" },
                        {name: "url", width: 1, hidden: true }
                    ],
                autowidth: true,
                treeGrid: true,
                ExpandColumn: "menu",
                rowNum: 200,
                ExpandColClick: true,
                treeIcons: { leaf: 'ui-icon-document-b' },

                loadComplete: function (rowid) {
                    var grid = $("#west-grid");
                    var gview = grid.parents("div.ui-jqgrid-view");
                    gview.children("div.ui-jqgrid-hdiv").hide();
                },

                onSelectRow: function (rowid) {
                    var treedata = $("#west-grid").jqGrid('getRowData', rowid);
                    if (treedata.isLeaf == "true") {
                        window.location = '<%= ResolveUrl("~/")%>' + treedata.url;
                    }
                }

            }
                    );