diff --git a/js/pacosako_ui.js b/js/pacosako_ui.js
index a1fdd1f..8e784f7 100644
--- a/js/pacosako_ui.js
+++ b/js/pacosako_ui.js
@@ -745,7 +745,7 @@ $(function (){
       }
    }
 
-   $('.cb-square').droppable({
+   $('.cb-square, .cb-phantom').droppable({
       accept: '.cb-piece',
       disabled: true,
       deactivate: function(ev, ui){