Hiding task-related variables and options, of which users should not be aware.
In order to facilitate the operation, many relevant parameters have default values set automatically at design time. Some parameters are of technical nature, with which users do not wish or need to bother. It is often assumed that most of the time users need not to be aware of these default values.
Hiding irrelevant situation information reduces the user's mental workload and facilitates the initial interaction.
Occasionally, users may need to change the value of a setup parameter, for example, for experimentation. Later, the user may forget the previous value or may forget to change it back. Eventually, on a shift change, subsequent users may not know about the value change.
Another problem is when the task needs are exceptional and require a change in setup parameters or in system variables. If these parameters are not displayed, the users may be unaware of the need to change them.
Updated on 29 Feb 2016.