比较简单,需要注意的是el-scrollbar须设置高度100%;

<div style="height: calc(100% - 120px);">
     <el-scrollbar style="height: 100%;">
             <file-manager-tree
                     @handleNodeClick="leftTreeNodeClick"
                     :treeList="menuTree">
             </file-manager-tree>
     </el-scrollbar>
</div>

TODO:源码解析