Stimulus: User expects/requires to use a keyboard (instead of a mouse) to navigate within the user interface, in all parts of the user interface.
Reaction: User can use the system with keyboard-only, without resorting to a mouse or trackpad.
Metric: Keyboard shortcuts are consistent. Functions that are identical or similar in different parts of the system (like “save”, “copy”, “paste”) have identical shortcuts throughout the system.
Background: User can use keyboard shortcuts to select and execute functions within the (graphical) user interface.