diff --git includes/menu.inc includes/menu.inc
index 83480eb..d038f50 100644
--- includes/menu.inc
+++ includes/menu.inc
@@ -1133,12 +1133,18 @@ function menu_tree_page_data($menu_name, $max_depth = NULL) {
         // parameters accordingly.
         if ($item['access']) {
           // Find a menu link corresponding to the current path.
-          if ($top_link = menu_link_get_preferred()) {
-            // Use all the coordinates, except the last one because there
-            // can be no child beyond the last column.
-            for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
-              if ($top_link['p' . $i]) {
-                $active_trail[$top_link['p' . $i]] = $top_link['p' . $i];
+          if ($active_link = menu_link_get_preferred()) {
+            // The active link may only be taken into account to build the
+            // active trail, if it resides in the requested menu. Otherwise,
+            // we'd needlessly re-run _menu_build_tree() queries for every menu
+            // on every page.
+            if ($active_link['menu_name'] == $menu_name) {
+              // Use all the coordinates, except the last one because there
+              // can be no child beyond the last column.
+              for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
+                if ($active_link['p' . $i]) {
+                  $active_trail[$active_link['p' . $i]] = $active_link['p' . $i];
+                }
               }
             }
           }