public readonly HashSet<HitTestTarget> lastMoveTargets = new HashSet<HitTestTarget>();
public readonly HashSet<HitTestEntry> _enteredTargets = new HashSet<HitTestEntry>();
readonly HashSet<HitTestEntry> _enteredTargets = new HashSet<HitTestEntry>();
void _handlePointerEvent(PointerEvent evt) {
if (evt is PointerScrollEvent) {