diff --git a/blocks/procedures.js b/blocks/procedures.js
index eb42047a7..6532da888 100644
--- a/blocks/procedures.js
+++ b/blocks/procedures.js
@@ -159,8 +159,8 @@ Blockly.Blocks['procedures_defnoreturn'] = {
       if (childNode.nodeName.toLowerCase() == 'arg') {
         var varName = childNode.getAttribute('name');
         this.arguments_.push(varName);
-        var variable = Blockly.Variables.getOrCreateVariable(this.workspace,
-            null, varName, '');
+        var variable = Blockly.Variables.getOrCreateVariablePackage(
+            this.workspace, null, varName, '');
         this.argumentVarModels_.push(variable);
       }
     }
@@ -217,8 +217,8 @@ Blockly.Blocks['procedures_defnoreturn'] = {
     while (paramBlock) {
       var varName = paramBlock.getFieldValue('NAME');
       this.arguments_.push(varName);
-      var variable = Blockly.Variables.getOrCreateVariable(this.workspace, null,
-          varName, '');
+      var variable = Blockly.Variables.getOrCreateVariablePackage(
+          this.workspace, null, varName, '');
       this.argumentVarModels_.push(variable);
       this.paramIds_.push(paramBlock.id);
       paramBlock = paramBlock.nextConnection &&
@@ -636,8 +636,8 @@ Blockly.Blocks['procedures_callnoreturn'] = {
     // And rebuild the argument model list.
     this.argumentVarModels_ = [];
     for (var i = 0; i < this.arguments_.length; i++) {
-      var variable = Blockly.Variables.getOrCreateVariable(this.workspace, null,
-          this.arguments_[i], '');
+      var variable = Blockly.Variables.getOrCreateVariablePackage(
+          this.workspace, null, this.arguments_[i], '');
       this.argumentVarModels_.push(variable);
     }
 
diff --git a/core/field_variable.js b/core/field_variable.js
index c0e3bb07a..53883e56a 100644
--- a/core/field_variable.js
+++ b/core/field_variable.js
@@ -88,7 +88,7 @@ Blockly.FieldVariable.prototype.initModel = function() {
     return; // Initialization already happened.
   }
   this.workspace_ = this.sourceBlock_.workspace;
-  var variable = Blockly.Variables.getOrCreateVariable(
+  var variable = Blockly.Variables.getOrCreateVariablePackage(
       this.workspace_, null, this.defaultVariableName, this.defaultType_);
 
   // Don't fire a change event for this setValue.  It would have null as the
diff --git a/core/flyout_base.js b/core/flyout_base.js
index 07f4a9096..50c38d5d7 100644
--- a/core/flyout_base.js
+++ b/core/flyout_base.js
@@ -250,6 +250,8 @@ Blockly.Flyout.prototype.init = function(targetWorkspace) {
 
   // Get variables from the main workspace rather than the target workspace.
   this.workspace_.variableMap_  = this.targetWorkspace_.getVariableMap();
+
+  this.workspace_.createPotentialVariableMap();
 };
 
 /**
diff --git a/core/variables.js b/core/variables.js
index 224aa20c6..0e2c5214a 100644
--- a/core/variables.js
+++ b/core/variables.js
@@ -385,7 +385,7 @@ Blockly.Variables.generateVariableFieldXml_ = function(variableModel) {
  *     or name + type combination.
  * @package
  */
-Blockly.Variables.getOrCreateVariable = function(workspace, id, opt_name,
+Blockly.Variables.getOrCreateVariablePackage = function(workspace, id, opt_name,
     opt_type) {
   var variable = Blockly.Variables.getVariable(workspace, id, opt_name,
       opt_type);
@@ -420,14 +420,15 @@ Blockly.Variables.getVariable = function(workspace, id, opt_name, opt_type) {
     if (!variable && potentialVariableMap) {
       variable = potentialVariableMap.getVariableById(id);
     }
-  } else if (opt_name && (opt_type != undefined)){
+  } else if (opt_name) {
+    if (opt_type == undefined) {
+      throw new Error('Tried to look up a variable by name without a type');
+    }
     // Otherwise look up by name and type.
     var variable = workspace.getVariable(opt_name, opt_type);
     if (!variable && potentialVariableMap) {
       variable = potentialVariableMap.getVariable(opt_name, opt_type);
     }
-  } else {
-    throw new Error('Tried to look up a variable by name without a type');
   }
   return variable;
 };
diff --git a/core/workspace.js b/core/workspace.js
index d4f9f27ae..a1428220d 100644
--- a/core/workspace.js
+++ b/core/workspace.js
@@ -95,7 +95,7 @@ Blockly.Workspace = function(opt_options) {
    * @type {!Blockly.VariableMap}
    * @private
    */
-  this.potentialVariableMap_ = new Blockly.VariableMap(this);
+  this.potentialVariableMap_ = null;
 };
 
 /**
@@ -197,7 +197,9 @@ Blockly.Workspace.prototype.clear = function() {
     Blockly.Events.setGroup(false);
   }
   this.variableMap_.clear();
-  this.potentialVariableMap_.clear();
+  if (this.potentialVariableMap_) {
+    this.potentialVariableMap_.clear();
+  }
 };
 
 /* Begin functions that are just pass-throughs to the variable map. */
@@ -469,7 +471,15 @@ Blockly.Workspace.prototype.allInputsFilled = function(opt_shadowBlocksAreFilled
  * @package
  */
 Blockly.Workspace.prototype.getPotentialVariableMap = function() {
-  return this.isFlyout ? this.potentialVariableMap_ : null;
+  return this.potentialVariableMap_;
+};
+
+/**
+ * Create and store the potential variable map for this workspace.
+ * @package
+ */
+Blockly.Workspace.prototype.createPotentialVariableMap = function() {
+  this.potentialVariableMap_ = new Blockly.VariableMap(this);
 };
 
 /**
diff --git a/core/xml.js b/core/xml.js
index 4d5a0a65e..fb695a48f 100644
--- a/core/xml.js
+++ b/core/xml.js
@@ -758,8 +758,8 @@ Blockly.Xml.domToFieldVariable_ = function(workspace, xml, text, field) {
     type = '';
   }
 
-  var variable =
-      Blockly.Variables.getOrCreateVariable(workspace, xml.id, text, type);
+  var variable = Blockly.Variables.getOrCreateVariablePackage(workspace, xml.id,
+      text, type);
 
   // This should never happen :)
   if (type != null && type !== variable.type) {