5.6.5.7 Size
Icons and symbols should be large enough for the user to perceive the representation and discriminate it from other icons and symbols.
5.6.5.8 Highlighting
An icon or symbol that the user has selected should be highlighted.
5.6.5.9 Scaling in Standard Intervals
Scales should have tick marks at a standard interval of 1, 2, 5, or 10 (or multiples of 10) for labeled divisions; intervening tick marks to aid visual interpolation should be consistent with the labeled scale interval.
5.6.5.10 Expansion of Graphic Displays
When a graphic display has been expanded from its normal coverage, some scale indicator of the expansion factor should be provided.
5.6.5.11 Unobtrusive Grids
When grid lines are displayed, they should be unobtrusive and not obscure data elements (e.g., curves, plotted points).
5.7 Interactive Control
5.7.1 General User Input Guidelines
5.7.1.1 Consistent Procedures
Procedures for entering commands or information should be consistent in form.
5.7.1.2 Standard Procedures
Standard procedures should be used for updating and deleting information.
5.7.1.3 Consistent Wording of Commands
All terms employed in the user-system interface, and their abbreviations, should be consistent in meaning from one transaction to another, and from one task to another.
5.7.1.4 Unnecessary Entry of Information
A user should not be required to re-enter information already available to the system.
5.7.1.5 Only Available Options Offered
Only control options that are actually available for the current transaction should be offered to users.
5.7.1.6 Control by Simultaneous Users
When several users must interact with the system simultaneously, control entries by one user should not interfere with those of another.
5.7.2 User Input Formats
5.7.2.1 Logical Ordering of Menu Options
Menu options should be ordered and grouped logically.
5.7.2.2 Consistent Design of Hierarchic Menus
The display format and selection logic of hierarchic menus should be consistent at every level.
