Horizontal tree with checkbox selection

Question

Is there a way to use a horizontal tree with selectionMode="checkbox"?

I have seen an example using PrimeFaces, but I needed this in PrimeNG.

I have tried this:

HTML

<p-tree
  [value]="files"
  layout="horizontal"
  selectionMode="checkbox"
  [(selection)]="selectedFiles"
></p-tree>

TS

import { Component } from '@angular/core';
import { NodeService } from './nodeservice';
import { TreeNode } from 'primeng/api';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
})
export class AppComponent {
  files: TreeNode[];

  selectedFiles: TreeNode;

  constructor(private nodeService: NodeService) {}

  ngOnInit() {
    this.nodeService.getFiles().then((files) => (this.files = files));
  }
}

You can try this code in this stackblitz project, but it doesn't seem to work.

Am I doing anything wrong or is it not supported?