Modes are intended to grab the user's full attention and to cause them to acknowledge the content present in them, in particular when critical confirmation from the user is required. This later use is criticised as ineffective for its intended use (protection against errors in destructive actions) due to habituation. Actually making the action reversible (providing an "undo" option) is recommended instead. Though modes can be successful in particular usages to restrict dangerous or undesired operations, especially when the mode is actively maintained by a user as a "quasimode".