Defining Predecessor Tasks
Most of the documentation about Tasks is found on https://success.support-works.com/#docviewer?doc=Supportworks-ITSM-Enterprise/Version-4.2.3/User-Guide/Task-Management
There is some mention of Predecessor tasks on https://success.support-works.com/#docviewer?doc=Supportworks-ITSM-Enterprise/Version-4.2.3/Administration-Guide/Managing-Business-Processes/Defining-Stage-Tasks/Creating-Details-for-a-Task/Defining-Predecessor-tasks
With normal tasks, once the task is created it will be displayed on the tasks list but with predecessor tasks, the behaviour is slightly different. If for example you have a Change Request and there a number of tasks and predecessor tasks involved in accomplishing the Change Request, when you first create the Tasks they will show against the Tasks list but if there are predecessor tasks, they will be hidden. This behaviour is correct because predecessor tasks must be completed first before the actual task is displayed.
If you first create First Task without a predecessor, which means it was not dependent on any other task, is displays on the Tasks list. But if you create a second task, which has the First task as its predecessor, the second task can not display until the First task is complete. Otherwise someone would select the second task and complete it before the first task is completed which would be wrong.