Project static duration

Gantt : Samples (dhtmlx.com)
Hello everyone, i’m wonder how to make my parent project being static when tasks are draging around.
It’s look like above sample link but used for both start and end date of project
Thank you !!

Hello,
In the sample, all tasks have the task type. So, each task has individual dates. Parent tasks only look like project tasks. In the onTaskDrag event handler, we limit the dates of a dragged task.
It will not work the same way if the parent task has the project type. In that case, it depends on the dates of its children:
https://docs.dhtmlx.com/gantt/desktop__task_types.html#projecttasks
So, if you limit the drag dates of a child task, it may affect the dates of the parent task.

You can see how it work in a simpler example:
https://snippet.dhtmlx.com/wasmow3j