diff --git a/dhtml_menu.module b/dhtml_menu.module
index 0f6df5c..9ba4226 100644
--- a/dhtml_menu.module
+++ b/dhtml_menu.module
@@ -24,7 +24,6 @@ function dhtml_menu_help($path) {
  * Adds CSS, Javascript and settings to the page.
  */
 function dhtml_menu_init() {
-  module_load_include('inc', 'dhtml_menu', 'dhtml_menu.theme');
   drupal_add_css(drupal_get_path('module', 'dhtml_menu') . '/dhtml_menu.css');
   drupal_add_js(drupal_get_path('module', 'dhtml_menu') . '/dhtml_menu.js');
   drupal_add_js(array('dhtmlMenu' => variable_get('dhtml_menu_settings')), 'setting');
@@ -46,3 +45,139 @@ function dhtml_menu_menu() {
   return $menu;
 }
 
+/**
+ * Preprocessor for menu_link.
+ * Adds the required HTML attributes and loads subtrees if necessary.
+ */
+function dhtml_menu_preprocess_menu_link(&$variables) {
+  $cookie = &drupal_static(__FUNCTION__);
+  $settings = variable_get('dhtml_menu_settings');
+
+  // Parse the cookie, if it is enabled.
+  if (!isset($cookie)) {
+    if ($settings['effects']['remember'] && $settings['nav'] != 'open' && $settings['effects']['siblings'] != 'close-all') {
+      $cookie = explode(',', @$_COOKIE['dhtml_menu']);
+    }
+    else {
+      $cookie = array();
+    }
+  }
+
+  // Saves a lot of code.
+  $l = &$variables['element']['#original_link'];
+
+  // Determine if the menu is blacklisted or not whitelisted.
+  $disabled = ($settings['filter']['type'] == 'blacklist') == !empty($settings['filter']['list'][$l['menu_name']]);
+  if (empty($l['menu_name']) || empty($l['mlid']) || $disabled) {
+    return;
+  }
+
+  // Add the ID and class attributes.
+
+  $variables['element']['#attributes']['id'] = 'dhtml_menu-' . _dhtml_menu_unique_id($l['mlid']);
+  $variables['element']['#attributes']['class'][] = 'dhtml-menu';
+
+  // If there are children, but they were not loaded, load them.
+  if ($l['has_children'] && !$variables['element']['#below']) {
+    $variables['element']['#below'] = _dhtml_menu_subtree($l['menu_name'], $l['mlid']);
+  }
+
+  // If the current item can expand, and is neither saved as open nor in the active trail, close it.
+  if ($l['has_children'] && !$l['in_active_trail'] && !in_array($variables['element']['#attributes']['id'], $cookie)) {
+    $variables['element']['#attributes']['class'][] = 'collapsed';
+    $variables['element']['#attributes']['class'][] = 'start-collapsed';
+  }
+}
+
+/**
+ * Traverses the menu tree and returns the sub-tree of the item
+ * indicated by the parameter.
+ *
+ * @param $menu_name
+ *   The internal name of the menu.
+ * @param $mlid
+ *   The menu link ID.
+ *
+ * @return
+ *   The tree below the menu item, as a renderable array, or an empty array.
+ */
+function _dhtml_menu_subtree($menu_name, $mlid) {
+  static $index = array();
+  static $indexed = array();
+
+  // This looks expensive, but menu_tree_all_data uses static caching.
+  $tree = menu_tree_all_data($menu_name);
+
+  // Index the menu tree to find ancestor paths for each item.
+  if (!isset($indexed[$menu_name])) {
+    $index += _dhtml_menu_index($tree);
+    $indexed[$menu_name] = TRUE;
+  }
+
+  // If the menu tree does not contain this item, stop.
+  if (!isset($index[$mlid])) {
+    return array();
+  }
+
+  // Traverse the tree using the ancestor path.
+  foreach ($index[$mlid]['parents'] as $id) {
+    $key = $index[$id]['key'];
+    if (isset($tree[$key])) {
+      $tree = $tree[$key]['below'];
+    }
+    else {
+      return array();
+    }
+  }
+
+  // Go one level further to go below the current item.
+  $key = $index[$mlid]['key'];
+  return isset($tree[$key]) ? menu_tree_output($tree[$key]['below']) : array();
+}
+
+/**
+ * Indexes the menu tree by mlid. This is needed to identify the items
+ * without relying on titles or stacks. This function is recursive.
+ *
+ * @param $tree
+ *   A tree of menu items such as the return value of menu_tree_all_data().
+ * @param $ancestors
+ *   Optional, used only by internal recursion.
+ * @param $parent
+ *   Optional, used only by internal recursion.
+ *
+ * @return
+ *   An array associating mlid values with the internal keys of the menu tree,
+ *   and all the mlids of the item's ancestors.
+ */
+function _dhtml_menu_index($tree, $ancestors = array(), $parent = NULL) {
+  $index = array();
+  if ($parent) {
+    $ancestors[] = $parent;
+  }
+
+  foreach ($tree as $key => $item) {
+    $index[$item['link']['mlid']] = array(
+      'key' => $key,
+      'parents' => $ancestors,
+    );
+    if (!empty($item['below'])) {
+      $index += _dhtml_menu_index($item['below'], $ancestors, $item['link']['mlid']);
+    }
+  }
+  return $index;
+}
+
+/**
+ * Keeps track of ID attributes and adds a suffix to make it unique-when necessary.
+ */
+function _dhtml_menu_unique_id($id) {
+  static $ids = array();
+  if (!isset($ids[$id])) {
+    $ids[$id] = 1;
+    return $id;
+  }
+  else {
+    return $id . '-' . $ids[$id]++;
+  }
+}