Not work collapse in Demo

[mydesign]

Prerequisites

• [ ] I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• [x ] The issue still exists against the latest master branch of yii2-tree-manager.
• [ ] This is not an usage question. I confirm having gone through and read the documentation and demos.
• [ ] This is not a general programming / coding question. (Those should be directed to the webtips Q & A forum).
• [ ] I have attempted to find the simplest possible steps to reproduce the issue.
• [x] I have included a failing test as a pull request (Optional).

Steps to reproduce the issue

Expected behavior and actual behavior

When I follow those steps, I see...

I was expecting...

Environment

Browsers

• [x ] Google Chrome
• [ x] Mozilla Firefox
• [ ] Internet Explorer
• [ ] Safari

Operating System

• [x ] Windows
• [ ] Mac OS X
• [ ] Linux
• [ ] Mobile

Libraries

• jQuery version:
• yii2-tree-manager version: last

Isolating the problem

• [x ] This bug happens on the demos page
• [ ] The bug happens consistently across all tested browsers
• [ ] This bug happens when using yii2-tree-manager without other plugins.