css中overflow-x: scroll不会出现横向拉条？

Question

css样式

.tree{
        overflow-x: scroll;
        white-space:nowrap;
        text-overflow:ellipsis;
        top: 19px;
        left: 66px;
        width: 124px;
        border: 1px solid #47a8ea;
        box-shadow: 2px 2px 2px #888888;
        float: none;
        background-color: white;
        position:absolute;
        z-index: 4;
    }

html代码

<div ng-show="is_show">
    <!-- as a Dom element -->
    <treecontrol 
        class="tree-classic tree" 
        tree-model="dataForTheTree" 
        options="treeOptions" 
        on-selection="showSelected(node)" selected-node="node"
         >
        {{node.name}}
    </treecontrol>
</div>

结果

Answer 1

要加在显示内容的外层div