Screen readers, switch devices, and eye trackers all rely on . They inject synthetic pointer events with zero physical movement.
By a recovering systems programmer
PointerFocus::register(target, |focus_state| match focus_state Active => button.highlight(true), Lost => button.highlight(false), ) This eliminates dribble because the framework deduplicates registration across frames. The focus state becomes part of the diff, not a side effect. pointer focus registration code
The best systems make pointer focus invisible. The worst make it unforgettable. Screen readers, switch devices, and eye trackers all rely on