[syslinux] Does advanced menu actually support ontimeout?

[Nazo]

I've finally gotten around to playing with the advanced menu, though
the complex example is definitely still beyond me.  I'm trying to
figure out a few basics from it, such as the tab key for line editing
(don't know what I've done wrong here since it seems like I copied
that part right) and the timeout.  It looks to me like the only
ontimeout implemented so far is an option to not even show the menu at
all if the user doesn't press a key within a certain time period. 
But, I want it to show the menu and simply time out after a while of
no keypresses.  Is there any way to implement this that doesn't
require several pages of code?  Have I just gotten mixed up and it
already does this but I copied that code wrong too?