diff --git a/grade/edit/tree/lib.php b/grade/edit/tree/lib.php
index da33c555898..74c0b76521b 100644
--- a/grade/edit/tree/lib.php
+++ b/grade/edit/tree/lib.php
@@ -188,7 +188,7 @@ class grade_edit_tree {
             $item = $category->get_grade_item();
 
             // Add aggregation coef input if not a course item and if parent category has correct aggregation type
-            $dimmed = ($item->is_hidden()) ? 'dimmed' : '';
+            $dimmed = ($item->is_hidden()) ? 'dimmed_text' : '';
 
             // Before we print the category's row, we must find out how many rows will appear below it (for the filler cell's rowspan)
             $aggregation_position = grade_get_setting($COURSE->id, 'aggregationposition', $CFG->grade_aggregationposition);