fix

 <template>
   <div id="app">
     <mu-drawer :open.sync="side_show" :docked="docked" :right="position === 'right'" :z-depth="1">
-      <mu-list>
-        <mu-list-item v-for="(v, k) in side_menu" :key="k" :to="v.url" @click="goTo()" button>
+      <mu-list :value="default_list_index" @change="listChange">
+        <mu-list-item :value="k" v-for="(v, k) in side_menu" :key="k" :to="v.url" @click="goTo()" button active-class="is-selected">
           <mu-list-item-title>{{ v.title }}</mu-list-item-title>
         </mu-list-item>
         <!-- <mu-list-item  @click="close" button>
@@ -59,6 +59,7 @@ export default {
   },
   data () {
     return {
+      default_list_index: 0,
       side_show: false,
       screen_width: '',
       docked: false,
@@ -90,6 +91,10 @@ export default {
     },
     goTo (v) {
       this.resize($('body').width());
+    },
+    listChange (v) {
+      //
+      this.default_list_index = v
     }
   }
 }
@@ -131,4 +136,8 @@ export default {
   width: calc(100% - 256px)
 }
 
+// .mu-item.is-selected {
+//     color: #2196f3;
+// }
+
 </style>