Adding multiple new tasks to the Gantt causes the browser to become unresponsive

[IvanDanchev]

Bug report

Reproduction of the problem

Reproducible in the demos (MVC and Core): https://demos.telerik.com/aspnet-mvc/gantt

1. Select a task in the Gantt's treelist (e.g., Market Research).
2. Click on the "Add Task" button in the Gantt's toolbar and select "Add child" from the dropdown.
3. Repeat step 2 until the browser becomes unresponsive.

Current behavior

The issue seems related to the _subtree method in kendo.treelist.js. This number of calls of this method increases with every new task. The time it takes for every next task to be added increases. After adding a few tasks _subtree is now called thousands of times every time a new task is added, which results in a Maximum call stack error.

Expected/desired behavior

Performance should not degrade when adding new tasks to the Gantt. The browser should remain responsive.

Environment

• Kendo UI version: 2022.2.621
• jQuery version: x.y
• Browser: [all]