const parentRect = getBoundingClientRect(parent);\n  const scrollParent = getScrollParent(children);\n\n  const styles = getStyleComputedProperty(parent);\n  const borderTopWidth = parseFloat(styles.borderTopWidth);\n  const borderLeftWidth = parseFloat(styles.borderLeftWidth);\n\n  // In cases where the parent is fixed, we must ignore negative scroll in offset calc\n  if(fixedPosition && isHTML) {\n    parentRect.top = Math.max(parentRect.top, 0);\n    parentRect.left = Math.max(parentRect.left,...