No option to assign Component when creating/editing Activities

https://civicrm.stackexchange.com/questions/17489/how-to-control-which-activity-types-options-appear-in-dropdown-when-creating-new/17618?noredirect=1#comment22947_17618

According the the CiviCRM User Guide https://docs.civicrm.org/user/en/4.7/organising-your-data/activities/

When creating or editing an Activity, there should be an option to assign that Activity to Contact or Case so that it is then available as an option to apply to a contact. This option is not there. There does not seem to be any way to add an activity to the dropdown choices.