使用angular2-multiSelect在IE11中没有出现滚动条

Question

<div *ngIf="showClient" class="form-group" id="selectClient">
    <label class="control-label col-sm-4" for="email"></label>
    <div class="col-sm-8">

        <angular2-multiselect [data]="dataList | OrderBy : 'itemName'" [(ngModel)]="selectedItems[dataList.id]" [settings]="dropdownSettings" name="multiSelect" (onSelect)="onItemSelect($event, dataList.id)" (onDeSelect)="OnItemDeSelect($event,dataList.id)" (onSelectAll)="onSelectAll($event)" (onDeSelectAll)="onDeSelectAll($event)" disabled>

            <c-item>
                <ng-template let-item="item">
                    <label style="color: #333;min-width: 160px;">{{item.itemName}}- {{item.id}}</label>
                </ng-template>
            </c-item>

        </angular2-multiselect>

    </div>
</div>

我还没有为此定义任何CSS。只是导入了angular2Multselect的默认CSS。

ScrollBar在chrome / fireFox中看起来很好..仅在IE中没有。请提出需要做什么。