Update commands.js
diff --git a/src/commands/math/commands.js b/src/commands/math/commands.js
index 4e1b823..f361a51 100644
--- a/src/commands/math/commands.js
+++ b/src/commands/math/commands.js
@@ -329,13 +329,13 @@
     super_.finalizeTree.call(this);
   };
   _.reflow = function() {
-     var $block = this.ends[R].jQ;//mq-sup
-     $block = $block.parent() ;//mq-supsub
+     var $block = this.jQ;//mq-supsub
 
      var h = $block.prev().innerHeight() ;
      h *= 0.6 ;
 
      $block.css( 'vertical-align',  h + 'px' ) ;
+
   } ;
 });