




The function redisplay-menu-bar updates the interface's menu bar, such that menus become enabled and disabled as appropriate.
When 
redo-items
 is non-nil, redisplay-menu-bar redoes the items in menu and menu-component that have an 
items-function
, by calling the 
items-function
 and setting the items. The default value of 
redo-items
 is t.
redo-items
 defaults to t in order to ensure that any accelerator associated with any item is up-to-date. When the menu bar contains menus (including sub-menus and menu-components) that have an 
items-function
, redisplay-menu-bar may take a relatively long time (tens of milliseconds). If it is called often (for example, each time the user types a character), then it is better to call redisplay-menu-bar with 
redo-items
 nil.
This function has been superseded by redisplay-interface, which updates the menu bar, but also updates other state objects such as buttons, list panels and so on.
CAPI User Guide and Reference Manual (Unix version) - 25 Feb 2015