jqGrid选择列控件向右拖拽超出边界处理

$("#tb_DeviceInfo").jqGrid('navButtonAdd', '#jqGridPager', {
                    caption: "选择列",
                    buttonicon: "ui-icon-newwin",
                    title: "",
                    jqModal: true,
                    position: "last",
                    onClickButton: function () {
                        $("#tb_DeviceInfo").jqGrid('columnChooser', {
                            dialog_opts: {
                                modal: true,
                                draggable: true,
                                resizable: false,
                                //minHeight: 350,
                                minWidth: 450,
                                show: 'blind',
                                hide: 'explode',
                                dragStart: function (event, ui) {
                                    var maxLeft = $(window).width() - 450;
                                    if (maxLeft < ui.offset.left)
                                        ui.position.left = maxLeft;
                                }
                            }
                        });
                    }
                });