Critical path functionality. A Project’s critical path represents the longest sequence of Tasks that must be completed on time to finish the Project. Not all projects have critical paths, and some projects have multiple possible paths. Critical paths can be highlighted with the “Show Critical Path” button on the Project’s Gantt chart.
By default, the slack — the gap between a successor Start Date and its predecessor Due Date — is 1 day; Tasks with more than a 1-day difference would not be part of a critical path. This can be changed with the custom setting “Critical Path Maximum Slack.”