Hook path in main menu not hold active trail In custom module names supply_area I've created custom path.

function supply_area_menu() {
    $items['supply-area'] = array(
        'title' =&gt; 'Supply area',
        'page callback' =&gt; 'supply_area_page',
        'type' =&gt; MENU_NORMAL_ITEM,
        'access callback' =&gt; true,
        'menu_name' =&gt; 'main-menu',
    );
    return $items;
}


Everything works perfectly except that even if I assign this path into main menu structure it does not hold menu structure so breadcrumbs looks like:
Home > Supply area and not Home > About > Supply area.
Is there something wrong with my hook_menu?
I am not sure what you are doing in a lot more areas of your system than described above, but doing the following on a d7 testbed here:

function MYMODULE_menu() {

  array $items;

  $items['about'] = array(
    'title' =&gt; 'About',
    'page callback' =&gt; 'MYMODULE_about_page',
    'type' =&gt; MENU_NORMAL_ITEM,
    'access callback' =&gt; TRUE,
    'menu_name' =&gt; 'main-menu',
  );

  $items['supply-area'] = array(
    'title' =&gt; 'Supply area',
    'page callback' =&gt; 'MYMODULE_supply_area_page',
    'type' =&gt; MENU_NORMAL_ITEM,
    'access callback' =&gt; TRUE,
    'menu_name' =&gt; 'main-menu',
  );

  return $items;

}

function MYMODULE_about_page() {
  return 'What\'s it all about, Alfie?';
}

function MYMODULE_supply_area_page() {
  return 'Making Supplies';
}


...followed by clearing caches and then setting it up via the Menu UI:



...provides the following:



so I would check how you might be doing it slightly differently on your system.