编辑器-导航-场景导航：分组内场景按照weight由小到大排列。没有weight则放在最后。

packages/code/src/Store/index.js

@@ -67,6 +67,17 @@ const store = new Vuex.Store({
                 // 如果属于上述二级分类
                 if (itemLevel2.id === itemLevel3.category /* 注意拼写！！！ */) {
                   itemLevel2.children.push(deepClone(itemLevel3))
+                  itemLevel2.children.sort((a, b) => {
+                    if (a.weight === undefined && b.weight === undefined) {
+                      return 0
+                    } else if (a.weight !== undefined && b.weight === undefined) {
+                      return -1
+                    } else if (a.weight === undefined && b.weight !== undefined) {
+                      return 1
+                    } else {
+                      return a.weight - b.weight
+                    }
+                  })
                 }
               }