code: function onItemClicked(instance, itemUi) {
      if (instance._dragSelectionStartOption) { // multi-select
        instance._dragSelectionStartOption = null
        return
      }
  
      if (instance._options.disabled || !isEnabledOptionUi(itemUi)) {
        return
      }
  
      instance._root.removeAttribute('data-szn-options--highlighting')
      instance._options.selectedIndex = itemUi._option.index
      instance._options.dispatchEvent(new CustomEvent('change', {bubbles: true, cancelable: true}))
    }
docs: Handles the user releasing the primary mouse button over an element representing an item.
  
  The function ends multiple-items selection for multi-selects, ends options highlighting and marks the the selected
  option for single-selects.
  
  @param {SznElements.SznOptions} instance The szn-options element instance.
  @param {Element} itemUi The element at which the user released the primary mouse button.