Dear Telerik,

Please check this example. The single difference than the original one from the demos section, is that I deleted the tasksDataSource.schema.model.fields.parentId.defaultValue". Now the default value of the parentId will be 0 instead of null. If you try to add a new task, the logic will break because of inifinity loop caused by the new task with id=0 and parent=the same task(parentId=0).

I checked the documentation at https://docs.telerik.com/kendo-ui/api/javascript/data/ganttdatasource/configuration/schema and this obligation is missing. It is something small that can save an hour to someone else. 

Best Regards, Boyan.