You might need to deactivate a Changeset so objects that belong to it can be used in another Changeset. An inactive Changeset is retained, but you cannot reactivate it.

To deactivate a Changeset, click it in the main Changeset window, click Deactivate in the Other Actions pane on the right, and then click Yes. From the main window of KCM Designer, click the navigation arrow icon on the toolbar, click Manage Changesets, and then repeat the action.