I have problems with horizontal scrolling. My mat-tree implementation is from [here](https://material.angular.io/components/tree/overview). Vertical scrolling works perfectly but horizontal doesn't work. How to add it to my mat-tree? By using an overflow parameter I see the horizontal scrolling bar but it doesn't work, doesn't react to content and it is still disabled. 

```
<mat-tree [dataSource]="dataSource" [treeControl]="treeControl">
  <mat-tree-node *matTreeNodeDef="let node" matTreeNodePadding>
    <button mat-icon-button disabled></button>
    {{node.item}}
  </mat-tree-node>
  <mat-tree-node *matTreeNodeDef="let node; when: hasChild" matTreeNodePadding>
    <button mat-icon-button
            [attr.aria-label]="'toggle ' + node.filename" matTreeNodeToggle>
      <mat-icon class="mat-icon-rtl-mirror">
        {{treeControl.isExpanded(node) ? 'expand_more' : 'chevron_right'}}
      </mat-icon>
    </button>
    {{node.item}}
    <mat-progress-bar *ngIf="node.isLoading"
                      mode="indeterminate"
                      class="example-tree-progress-bar"></mat-progress-bar>
  </mat-tree-node>
</mat-tree>

```

```
.example-tree-progress-bar {
  margin-left: 30px;
}

```