I initially created a resource datastore and then filled it with some resources. The display works and calculates everything correctly.
Then I have reset the gantt with
clearAll() and removed all tasks. This also removed all resources from the resource datastore.
Now I loaded new tasks, which automatically bring new resources with them, which I saved in the resource datastore. The display works fine at first:
But when I try to unfold department 3, I get the following error: