We have a bug in the tracker regarding saving the open state. It will be fixed in the future. I cannot give you an ETA, but I will notify you when the fix is ready.
Now, as a workaround, you can save the IDs of open tasks before parsing the data, then open those tasks:
Please, tell me if it doesn’t work for other properties.
If a task already exists, Gantt updates the parameters of that task. In the following snippet, you can see that initially, “Task #2” has
custom_property. After you parse the data, the name changes, and there is no
If you have the data that don’t have some tasks that you have in the chart, Gantt won’t delete those tasks after you load the data. And it is expected behavior because it is a function of loading the data, not of reloading the data and not of deleting the data. It allows loading one task without deleting all existing tasks. If you need to remove the tasks, you can use
gantt.clearAll() before loading the data: