You see the difference between the two ways of defining the [tt]&startId[/tt] if you use it in the same template for pages on different levels:
&startId=`[[UltimateParent? &top=`[[*parent]]`]]`
In this case every page will display a submenu of just one level (the next one down in the tree, showing the "children" of the page).
&startId=`[[UltimateParent? &topLevel=`1`]]`
Here, depending on its level, a page will show more than one submenu, starting always with the same upper level and going down to its immediate children.
Edit:
Changed formatting of the code, was eaten up by the forum before.
[ed. note: ottogal last edited this post 13 years, 11 months ago.]