Mac menubar question

[depstein at att.net]

A group of buttons can be used as a Mac menubar, but 
there are some differences in behavior between how those 
menus work and how the buttons work if they are used 
directly, e.g., displayed in a palette.  It appears that 
I cannot change the contents of a Mac menubar menu "on 
mousedown," while I can do that if the button itself is 
pressed from a palette.  And the Mac menubar doesn't 
seem to set the "menuHistory," while the button itself 
does.

I conclude that some subset of button functions works 
when the button is in the Mac menubar.  Has someone 
documented exactly what that subset is?

Many thanks.

David Epstein