Simletree menu collapse all but clicked

[merlijn]

1) Script Title:
SimpleTreeMenu

2) Script URL (on DD):
http://www.dynamicdrive.com/dynamicindex1/navigate1.htm

3) Describe problem:
I successfully implemented SimpleTreeMenu. Thank you for the script.
What should I do to close all other menu-items when clicked on a main category?

I modified it to show only one level of submenus:

[ MAIN1 ]
--sub1
--sub2

[ MAIN2 ]
--sub1
--sub2

[MAIN3]
--etc.

What I'd really like is when I click on MAIN2 or one of it's subs, that MAIN1 and MAIN3 collapse until clicked on....

Thank you!