To create a friendly user experience during the configuration process, questions that are not relevant should not be asked and options that are not available should not be offered. For example, there is no need to ask if a car shall be delivered with a charging cable if the user has selected a petrol engine. Therefor rules are needed to control when parameters and values are shown or hidden.

There is also a need for hiding parameters and values in the production environment during the preparation of options that have not yet been released, see site effectivity for rules.

Parameters and multi choice values are hidden using sub parameter rules

There are two types of rules for hiding parameters, sub parameter rules and sub parameter expression rules. The difference is if the trigger for showing parameters is defined by parameter/value combinations or by a Boolean expression.

Lookup values and multi choice values are hidden using disallowed combination rules

Lookup values are hidden by making the values disallowed through disallowed combination rules. However, by default disallowed values are shown as disabled and the user can click on the values to get information about how to make them selectable (if possible). For disabled values to become hidden either the option Hide if disabled need to be set for the lookup value or the option Hide values if disabled for the parent lookup parameter which affects all its values.

The same behavior applies for hiding multi choice values, though the setting for hiding multi choice values is only found at the value level and hiding occurs when Checked is disallowed, not when Unchecked is disallowed.