Task Manager is the mechanism for adding and maintaining Tasks and Task Groups in an issue, Recurring Issue or Quick Pick. The Task Manager is also used to build out workflows with process options that change issue values or trigger additional Task Groups to be added to the issue.
The Task List is displayed on issues where there are existing tasks. It consists of a summary list of Tasks with the Task Manager button on the left. If there are no existing tasks in an issue, this list will be blank and the Task Manager button will still appear on the left.