Systems, methods, and other embodiments for providing management of activities of a project plan associated with a computer application are described. In one embodiment, a calendar view of an activity is edited to change a number of calendar time units over which the activity is to be performed. In response to updating the calendar view of the activity, resource data structures are updated for multiple resources assigned to the activity. The resource data structures are updated to reflect the change in the number of calendar time units for each assigned resource. For each assigned resource, the number of calendar time units corresponds to a period of time for which the resource is assigned to the activity.