diff --git a/core/block.js b/core/block.js
index ae49a86015..125744dfda 100644
--- a/core/block.js
+++ b/core/block.js
@@ -121,6 +121,12 @@ Blockly.Block = function(workspace, prototypeName, opt_id) {
    */
   this.isShadow_ = false;
 
+  /**
+   * @type {boolean}
+   * @private
+   */
+  this.isShadowArgument_ = false;
+
   /**
    * @type {boolean}
    * @protected
diff --git a/core/scratch_blocks_utils.js b/core/scratch_blocks_utils.js
index aa44203c5d..ab05555d0a 100644
--- a/core/scratch_blocks_utils.js
+++ b/core/scratch_blocks_utils.js
@@ -84,7 +84,7 @@ Blockly.scratchBlocksUtils.changeObscuredShadowIds = function(block) {
  */
 Blockly.scratchBlocksUtils.isShadowArgumentReporter = function(block) {
   return (block.isShadow() && (block.type == 'argument_reporter_boolean' ||
-      block.type == 'argument_reporter_string_number'));
+      block.type == 'argument_reporter_string_number' || block.isShadowArgument_));
 };
 
 /**