How to achieve the task scheduling time and the task actually time consuming.
Tasks in GanttProject have only one duration, one which is currently actual. However, you can save baselines and compare how tasks durations changed over the time. Check out “Baselines” button above the Gantt chart.
I didn’t understand the “baseline” at first. But after setting the “baseline”, and after adjusting the date at will, the miracle appeared.
Thank you very much for your help. This tool is great.