VUE loading Loading.service(option) loading 被 dialog挡在下面

     var option = {
                lock: true,
                text: '加载中...',
                spinner: 'el-icon-loading',
                background: 'rgba(0, 0, 0, 0.7)'
            }; 
     const rLoading = Loading.service(option);
     let BOX = document.querySelector(".openSidebar");
         BOX.style.zIndex = "999"