in src/lib/utils/tooltip.ts [375:391]
function updatePositions() {
updateElementPosition(tooltipMask, {
top: `${node.getBoundingClientRect().top + window.scrollY}px`,
left: `${node.getBoundingClientRect().left + window.scrollX}px`,
width: `${node.getBoundingClientRect().width}px`,
height: `${node.getBoundingClientRect().height}px`
});
const positions = computePosition(
node.getBoundingClientRect(),
tooltipElt.getBoundingClientRect(),
opts
);
updateElementPosition(tooltipElt, positions.float);
updateElementPosition(arrowElt, positions.arrow);
}