function isUpperIntersecting (newItem, existing) {
  return (newItem.to >= existing.from) && (newItem.to < existing.to) && (newItem.from < existing.from)
}
Examples:
existing: 20-25 | 20-25
new_item: 15-22 | 15-20
@param {MinimalSelectionItem} newItem
@param {MinimalSelectionItem} existing
@returns {boolean} returns true if the new item's upper end is intersecting with the existing item