If your project uses UCM, you must set your view to an activity before you create versions. You must choose an activity at least once while working on a project (however, you should use many activities to describe your work). Thereafter, if you do not choose a different activity, all new versions are assigned to the original activity.
By default, if you work on a UCM project, you are prompted to create a new activity or choose an activity after you close the "Check out items" window or the Add Files to ClearCase/Add to Source Control window.
If you changed default behavior so that you are not prompted for an activity, from the "Check out items" window or the Add Files to ClearCase/Add to Source Control window, click Advanced and, from the Activities page of the Options window, perform one of the following actions:
If your UCM project is enabled for Rational ClearQuest®, you can find and set activities from your Rational ClearQuest to-do list.