RichFaces Drop Down menu is a component that allows to organize the hierarchical menu
similar to one that almost every desktop application has.
The drop down menu has a label that always appears on the page and invisible panel
that appears with a particular client side event (onmouseover, onclick etc). The event is
defined with an 'event' attribute.
Drop Down Menu can contains a set of Menu Items, Menu Groups and Menu Separators.
Group plays a role of label for secondary levels on the menu. Separator is represented with
horizontal lines between the items or groups. An item is an active element that might produce
Ajax or non-Ajax requests. The submittion mode is defined with 'submitMode' attribute that has
three possible options - "server", "ajax" or "none". Mode "none" does not produce any request, but
allows you to provide your own functionality inside the menu item with an inline content.