




The class 
popup-menu-button
 provides a button with a popup menu, which is displayed when the user clicks on the button.
If 
menu-function
 is non-
nil
, it should be function of one argument (the pane) and should return a menu object.  Otherwise, 
menu
 should be a menu object.
popup-menu-button
 inherits from item, so you can supply 
text
, 
data
 and so on.