Activity Center uses two view modes to display the list of projects and activities. One is flat view mode, where activities and sub-activities are not distinguishable one from the other. The other one is hierarchical view mode where a margin is used to tell a sub-activity from its parent. Refer to Hierarchical/flat view mode for details.

To add a sub-activity, use hierarchical view mode.

Adding a sub-activity:

1. In Activity Center, switch to hierarchical view by clicking the respective view selection button ().
2. Hover the mouse pointer over the activity you want to add a sub-activity to.
3. As the add sub-activity button pops up (), click it.
4. Give a name to the sub-activity.
5. Press Ctrl+Enter if you want to add another sub-activity on the same level, or
6. Press Enter, or click anywhere on the screen to finish adding the sub-activity.
7. As the screen refreshes and you see the sub-activity placed under the parent activity you can go to its details page and supply any extra details as may be needed. See steps 5 through 9 in Creating activities in Activity Center.