tk_OptionMenu and scroll

Hi all,

I'm implementing a simple option menu by passing in a list during
construction then setting the starting element as the first in the
list such as :

eval tk_optionMenu .departureCombo origin $cities
set origin [lindex $cities 0]

The $cities list holds about 150 items in it. In windows the
optionmenu appears with a couple of arrows appearing so you can scroll
through to the other options that cannot be seen as the list is too
big. This does not happen under Linux. Has any body come across this
vefore or know how i can forcibly specify a scrollbar to attach to the
optionMenu?

Many thanks

.