Issue with collapsible sub-tasks

[prjangid27]

Hi team,
I am using highchart's Gantt Chart to create a task which has multiple subtasks.

1. Current implementation is using an external button to input a task name and attaches an appropriate parent to the task.
2. While it is working fine, I wish to have a label like "+ Add a new Task" on clicking it a modal opens and a task is assigned an appropriate parent here as well.

The problem with the approach 2. has been that when I am collapsing the main task 1 under which there are multiple subtasks, the main task 2 is also lost from the screen. The chartRef.current has all the data intact but on an attempt at collapsing, the UI is not what one expects.

I wish to seek some assistance with how Highcharts internally deals with the collapsing of the tasks feature. Also if you have any coding reference to this problem it would be great as I am not able to figure this out.

Video Reference of the correctly working approach (approach 1):
[https://drive.google.com/file/d/1XmLIuN ... drive_link][/https://drive.google.com/file/d/1XmLIuN ... drive_link]

Video Reference of the incorrectly working approach (i.e. approach 2):
[https://drive.google.com/file/d/1hNKHo1 ... sp=sharing][/https://drive.google.com/file/d/1hNKHo1 ... sp=sharing]

Code:
https://codefile.io/f/CugWFKXCvS

I know you are not obliged to go through the code and help at that depth, but any guidance you could offer or show any coding mistake would be greatly appreciated.

[prjangid27]

The issue has been resolved. I had been assigning same id to each label hence the issue.