I cannot delete a resource inside a task

Using Gantt 2.8.5 on Mac OS-X, I found that I cannot delete a resource from within the Properties - Resources tab. In the resources tab I can delete the resources. But after closing the properties pop-up window, nothing has changed in the resources tab.

I can delete the resources from the resources chartt in Gant main window.

Any solutions?

Please look at this ticket in the tracker: https://github.com/bardsoftware/ganttproject/issues/612
TL;DR: select resource by clicking its Id in the table rather than its name.