Chapter 6: User Interfaces for Mobile Media 245 requires the designer to understand that the users have often devel- oped their own style for working. Therefore, it is benefi cial to support UI customization and personalization. 6.4.1.5 Aid the User Aid to the user is important, since they may still be in the learning phase, and not yet aware of all available possibilities, or the task may have been interrupted for a while and the user is returning to it. Aiding the user also minimizes cognitive load. Therefore, the UI should com- municate its current state, especially if the state limits the availability of features or navigation steps, such as in an edit mode, where the user is only able to change the values of the object’s attributes instead of using the object. As far as mobile devices are concerned, online help is a primary source of assistance, since it is unlikely that the user has any other additional help material available. It is expected that the user will need to fi nd information about some actions, also when not trying to recover from an error. To make this easier, the system should know or predict what the user wishes to accomplish, based on, for instance, the state of the system and available objects. The system should direct the user with clues and hints on what are possible and typical actions, and how they could be performed faster. For example, the shortcut key shown next to the menu item’s label educates the user to use an accelerator; bolding the default menu item suggests the most typical command; and disabling items shows what cannot be done now. The order of actions in a menu or toolbar may represent the frequency of use and so frequent commands require less navigation steps. Similarly, the layout can be used to emphasize impor- tance, or the order of fi lling in information. If the order of fi lling is related to critical and rare tasks, the UI may contain a wizard, which divides the task into a set of steps and associ- ated views and controls, which the user must perform in a specifi c order. The wizard structures the task and assists the user to perform actions in the correct order, and to input required information by showing only the controls and information that are relevant to each step. Obviously, the wizard is not fl exible, as it controls the task fl ow instead of the user. Consequently, wizards should be used sparingly in the UI. Because text input with mobile devices is slower than with desktop computers, the UI designer should think of ways to reduce it. A tech- nique referred to as auto-fi ll tries to predict what data the user wishes to input in a certain fi eld based on, for instance, the system’s and the application’s states, the type and the format of the input fi eld, the