--- includes/common.inc	2009-10-13 16:22:23.000000000 +0200
+++ includes/common.inc.new	2009-10-13 16:22:12.000000000 +0200
@@ -2579,7 +2579,7 @@ function drupal_get_js($scope = 'header'
   foreach ($items as $item) {
     switch ($item['type']) {
       case 'setting':
-        $output .= '<script type="text/javascript">' . $embed_prefix . 'jQuery.extend(Drupal.settings, ' . drupal_to_js(call_user_func_array('array_merge_recursive', $item['data'])) . ");" . $embed_suffix . "</script>\n";
+        $output .= '<script type="text/javascript">' . $embed_prefix . 'jQuery.extend(Drupal.settings, ' . drupal_to_js(call_user_func_array('array_merge_recursive_distinct', $item['data'])) . ");" . $embed_suffix . "</script>\n";
         break;
 
       case 'inline':
@@ -4218,3 +4218,43 @@ function _drupal_flush_css_js() {
   }
   variable_set('css_js_query_string', $new_character . substr($string_history, 0, 19));
 }
+
+/**
+ * array_merge_recursive does indeed merge arrays, but it converts values with duplicate
+ * keys to arrays rather than overwriting the value in the first array with the duplicate
+ * value in the second array, as array_merge does. I.e., with array_merge_recursive,
+ * this happens (documented behavior):
+ *
+ * array_merge_recursive(array('key' => 'org value'), array('key' => 'new value'));
+ *     => array('key' => array('org value', 'new value'));
+ *
+ * array_merge_recursive_distinct does not change the datatypes of the values in the arrays.
+ * Matching keys' values in the second array overwrite those in the first array, as is the
+ * case with array_merge, i.e.:
+ *
+ * array_merge_recursive_distinct(array('key' => 'org value'), array('key' => 'new value'));
+ *     => array('key' => array('new value'));
+ *
+ * Parameters are passed by reference, though only for performance reasons. They're not
+ * altered by this function.
+ *
+ * @param array $array1
+ * @param array $array2
+ * @return array
+ * @author Daniel <daniel (at) danielsmedegaardbuus (dot) dk>
+ * @author Gabriel Sobrinho <gabriel (dot) sobrinho (at) gmail (dot) com>
+ */
+function array_merge_recursive_distinct(array &$array1, array &$array2)
+{
+  $merged = $array1;
+  foreach ($array2 as $key => &$value)
+  {
+    if (is_array($value) && isset($merged[$key]) && is_array($merged[$key])) {
+      $merged[$key] = array_merge_recursive_distinct($merged[$key], $value);
+    }
+    else {
+      $merged[$key] = $value;
+    }
+  }
+  return $merged;
+}