Setting MenuButton on openCard

[Mikey]

I'm trying to use a menu button to display the name of the current card.

So, I have done the following:
1) the text of the button contains the names of all cards
2) the button is a group
3) In the script for the group is the following
on openCard
   set the menuHistory of button "menu" to the number of this card
end openCard

However, when I either send openCard or navigate, nothing happens
visually, i.e. the option menu doesn't change its label, UNTIL I
manually change it once by clicking on it.  Then it works as expected.

BEFORE manually changing it, the menuHistory and the label are what I
would expect them to be, but the display is improper.

XP/SP2, Studio 2.8.1.

Mike.