Required library edition:
Required library file: dhtmlxmenu.js

adds a new sibling item

• nextToId - id of the element after which a new one will be inserted
• itemId - id of a new item
• itemText - text of a new item
• disabled - true|false, whether the item is disabled or not
• img - image for the enabled item
• imgDis - image for the disabled item

    menu.addNewSibling(nextToId, itemId, itemText, disabled, imgEnabled, imgDisabled);