Active is an option for ButtonBox, Cell and Notebook which specifies whether a button should be active.
With Active->False the contents of a button can be edited.
With Active->True a button will perform an action when it is clicked.
Active cells are indicated by an A in their cell bracket.
See Section 2.9.10, Section 2.11.6 and Section 2.11.9.
See also: ButtonStyle, Evaluator.
New in Version 3.