How to handle task which have start date as null?

Gantt
#1

I am using Gantt chart to show task.
In my case many task have start date as null, for which gantt chart automatically take 1Dec 1969. how to handle this.

#2

Hello,
If tasks don’t have start_date, you can add unscheduled parameter to them before parsing the data:
https://docs.dhtmlx.com/gantt/desktop__unscheduled_tasks.html
Here is a snippet demonstrating how it works:
http://snippet.dhtmlx.com/5/7030ab44a