FNC Gantt Chart's export routines not always working

We are using FNC Gantt Chart 1.3.3.1. While the PDF export demo is working, PDF export is not working for other project task structures, especially those with one root (top-level) task without a WBS number and all other tasks being sub-tasks of the root task with WBS numbers. We found that the functions TTMSFNCGanttProject.GetTaskByCount and TTMSFNCGanttProject.GetNextTask are causing the issue which rely on every top-level project task to have a WBS no. Thus, on PDF export, they only return the root task and then return nil.

Could you please explain how you you make a task without WBS number?

Ok. We have extended the FNC Gantt Chart to set a custom WBS number, since the model data already provides the WBS number.