Menu systems should clearly indicate which options are selectable.
Additional Information:
Two techniques for preventing users from selecting inappropriate options are to present (1) only relevant options and exclude the others, and (2) all options, using a code to designate those that are relevant or available. Three considerations regarding the appropriateness of these methods include the type of options presented (e.g., actions versus destinations), the number of options associated with each node, and the number of options that are applicable to multiple nodes. For example, there may be many options representing destinations in the information structure and only a few of them may be relevant to a particular location in the display network (e.g., the number of parent and descendant nodes that can be accessed from a given node is small compared to the total number of nodes in the network). Thus, for menus containing destination options, it would seem practical to present only the relevant options, rather than all options, and use a code to designate those that are relevant or available. Compared to destination options, options that indicate actions may be more limited in number. In addition, action options may apply to multiple nodes (e.g., the same set of actions may be applicable to a large number of display pages). In such cases, it may be possible to present all options and use a code to designate those that are appropriate. Presenting the irrelevant or unavailable action options using a low-salience code may reinforce learning of the locations of options on the menu panels and, thus, decrease option selection time. The relative advantages of these two methods are not fully understood. In addition, the effects of using both methods in combination (e.g., for menu systems that contain both action and destination options) are not fully understood.