Newbie here but just wanted to share a quick tip: separate root categories from subcategories; maintain the subcategories menu even if clicking on a link within the subcategories; and most importanty (at least as my needs were concerned)...use the parent category as a header ("you're here") indicator. Although the "you're here" indicator I cooked up, the rest was provided by a helpful person on the forum. Thanks for helping me get through this project.
Code:
{if ($navigation_page eq "")||($navigation_page eq "1")}{strip}
{section name=position loop=2}
{if not %position.first%}{$location[position].0}{/if}
{if $location[position].0 ne "" }{/if}
{/section}
{/strip}{/if}
{section name=cat_num loop=$allcategories}
{if $allcategories[cat_num].parentid eq $location[1].1|replace:"home.php?cat=":""}
{ $allcategories[cat_num].category|escape }
{/if}
{/section}