diff --git a/modules/ext.categoryTree.styles.less b/modules/ext.categoryTree.styles.less
index 8f8063d2..5113c63d 100644
--- a/modules/ext.categoryTree.styles.less
+++ b/modules/ext.categoryTree.styles.less
@@ -92,7 +92,7 @@
 }
 
 .CategoryTreeEmptyBullet {
-	.expandable-arrow( @color-disabled );
+	.expandable-arrow( @background-color-disabled );
 }
 
 /* Hide toggle buttons for clients without JavaScript */