function isLowerIntersecting (newItem, existing) {
  return (newItem.from <= existing.to) && (newItem.from > existing.from) && (newItem.to > existing.to)
}
Examples:
existing: 1-10 | 1-10
new_item: 8-12 | 10-15
@param {MinimalSelectionItem} newItem
@param {MinimalSelectionItem} existing
@returns {boolean} returns true if the new item's lower end is intersecting with the existing item