diff --git a/demos/blockfactory/blocks.js b/demos/blockfactory/blocks.js
index 5a310cecb..7f6da073f 100644
--- a/demos/blockfactory/blocks.js
+++ b/demos/blockfactory/blocks.js
@@ -610,7 +610,7 @@ Blockly.Blocks['type_group_item'] = {
 
 Blockly.Blocks['type_null'] = {
   // Null type.
-  valueType: 'null',
+  valueType: null,
   init: function() {
     this.setColour(230);
     this.appendDummyInput()
diff --git a/demos/blockfactory/factory.js b/demos/blockfactory/factory.js
index 4aa9dee5b..a4a158e7a 100644
--- a/demos/blockfactory/factory.js
+++ b/demos/blockfactory/factory.js
@@ -257,10 +257,10 @@ function getOptTypesFrom(block, name) {
   var types = getTypesFrom_(block, name);
   if (types.length == 0) {
     return '';
-  } else if (types.length == 1) {
-    return types[0];
   } else if (types.indexOf('null') != -1) {
     return 'null';
+  } else if (types.length == 1) {
+    return types[0];
   } else {
     return '[' + types.join(', ') + ']';
   }