Unable to add `Resources` as a column to Gantt chart

[DmitryBarashev]

Can't access GanttProject 2.8.10

In this dialog black/gray colors mean that column is currently shown or hidden. You can select gray rows in the list and once they are selected, “Show selected” button makes them visible in the table. It might not be the best UX, but it has been working this way in GanttProject for years.