An interactive control should not require one particular pointing device when the task can be expressed through other input methods.

Keyboard focus identifies which control will receive keyboard interaction. Focus order should follow a meaningful task sequence, and the focused element should remain visibly distinguishable.

A user must be able to enter, operate and leave interactive components without becoming trapped. Custom widgets that respond only to pointer clicks can become unusable when they do not expose equivalent keyboard actions and state.

Pointer, keyboard, switch, voice and assistive input can all activate the same underlying command when the interface separates what action is requested from which device generated it.

Focus should move deliberately after major interface changes. Unexpectedly resetting it to the beginning or moving it to hidden content can disorient users who navigate sequentially.

Input-independent design makes interaction semantics primary and the physical input device one way of invoking them.