Users should be allowed to control the processing of information or commands by explicit action.
Additional Information:
The processing of an entry or the cancellation of an ongoing process should not occur as a side effect of some other action. For example, when a user is keying an extended data entry, the computer should not interrupt the user to require immediate correction of any entry error, but instead should wait for the user's ENTER action. Also, when a user is composing a command to accomplish some transaction, the computer should not interrupt the user by responding as soon as it recognizes a partial entry, but instead should wait for the user's ENTER action. In automated process control applications, emergency conditions may take precedence over current user transactions, and a computer-generated warning might interrupt user actions. In routine, repetitive data entry transactions, successful completion of one entry may lead automatically to initiation of the next. Computer detection of problems with current user entries can usually be negotiated at the conclusion of a transaction, before it is implemented. Nondisruptive alarms or advisory messages can be displayed to report computer monitoring of external events so that the user can choose when to deal with them.