Recipes for Breadcrumbs, Categories and Category-Specific Nav Menus?

I had the same issue. I have got it working using a custom php snippet. I use this from the page.tpl.php file, but it can be added to a custom block.

tip: Whatever approach you take do not try to modify your menus to get this to work! That's whats driving your breadcrumbs, and they also seem to constantly change when you are using the category module if they are outside the primary links menu (or whatever menu you have defined as containing your primary navigation).

So try this:

    $localNav = _menu_get_active_trail();
    if($localNav[1] && $user->uid != 1) {
      $local = theme_menu_tree($localNav[1]);
    	if($local):?>
        <div class="block" id="localNav">
        <h2 class="sidebarTitle">Current Section: <strong><?php $currentHeading = menu_get_item($localNav[1]);print $currentHeading['title'] ?></strong></h2>
    	  <?php print $local; ?>
        </div>
      <?php else: ?>
        <div class="sidebarTitle"></div>
  	  <?php endif;

The html can be customised to whatever your want it to be. It basically looks for the active current menu which, if you are working with a strict hierarchical structure, should always be your primary links for an anonymous user. You dont need to modify your menu structure for this to work.

You could refine it to check for the primary links menu, and only build the block if the current page fitted within that structure. I have not had any need to do that yet, but it would be a simple if statement.

The test for $user->uid==1 checks for admin, it gets a bit ugly when your admin menu pops up twice. You may want to change this.

This works of a standard primary links menu, so you dont need to muck around with your menu structure.

hth

ethanw, there is indeed a way out. Steps:

1. Create a menu called 'About Us' at administer>>menus>>add menu
2. Go to administer>>settings>>category, click on 'Menu item settings' and choose 'About Us' as the default menu and save the changes
3. Go to administer>>categories and create a new container. Make sure this is a hidden container
4. Now create the category structure for the 'About Us' section using containers and categories. Create an 'About Us' container, with History, Contact info and legal as the categories. This container should have the hidden container as its parent.
5. Go to administer>>menus, find the primary links menu, add a menu item called 'About Us', with the path being either the node id or the alias (if you are using cat_pathauto). Tick the 'Expanded' check box if you want the About Us menu to display expanded. Choose the parent item as 'Primary links'.
6. Go to administer>>blocks, enable the 'About Us' block and configure it to show only on the 'About Us' pages and save the changes.

Repeat this process for the other primary links you want to show with a sectional navigation menu.

Sit back and enjoy lovely primary links leading to sectional navigation menus without breaking the breadcrumb trail, the prev/up/next navigation of category_display etc etc :-)

Note: This is based on the multiple root menus tutorial on Jaza's category web site. One word of caution- before you create each new sectional nav block, you should change the default menu at administer>>settings>>category>>menu item settings. Otherwise, your menu navigation links will land up in the wrong sectional menu. Also heed the other warning in the tutorial I referred to. But, that's a minor one.