diff --git a/dev/js/src/vc/docgroupref.js b/dev/js/src/vc/docgroupref.js
index 905faf8..7d3ecea 100644
--- a/dev/js/src/vc/docgroupref.js
+++ b/dev/js/src/vc/docgroupref.js
@@ -76,6 +76,7 @@
       }
       else {
         this._refE.addT(loc.EMPTY);
+        this._refE.classList.add('unspecified');
       };
 
       // Change value