The SelectManyMenu tag renders an HTML "select" element with the "multiple" attribute present and the "size" attribute set to 1. This component is designed for situations where you want to display a list of menu items to the user that allows the selection of multiple options using a menu that displays one item at a time.
The main difference between select lists and menus in
JSF is the "size" attribute. Menus always have a size of one, while lists can have a variable size.