However, it is possible to load tasks without dates. In that case, the dateless tasks will obtain the date parameters from their children or from other tasks.
But those tasks cannot be the first one that you load: http://snippet.dhtmlx.com/05ced85c4 http://snippet.dhtmlx.com/bc8fdfc9f
If you want to have something like projects, you can assign any date in the onTaskLoading event handler. After adding children, you will be able to see the task, and after you drag or resize children, the parent task will be resized: http://snippet.dhtmlx.com/a0e68e798