The full definition follows.
Content always determines what constitutes an active element.
The role of an element as an active element is subject to applicability. The state of the user's interaction with that content may limit which elements are active. The user may interact with content without necessarily activating active elements. For example, selecting an element's text and copying it to the clipboard is clearly user interaction but does not make that element an active element. The consequence of triggering an active element depends on the element.