Update UserDataMultiDefault to use the new definition of the combo.select event.

static/track_events/src/form/field/UserDataMultiDefault.js

@@ -139,14 +139,13 @@ Ext.define('TrackEvents.form.field.UserDataMultiDefault', {
     // supersede the base class method to deal with the data type
     //
     // @param {Ext.form.field.ComboBox} combo
-    // @param {Ext.data.Model[]} records
+    // @param {Ext.data.Model} record
     //
     //
-    onComboBoxSelect: function (combo, records) {
+    onComboBoxSelect: function (combo, record) {
 
         "use strict";
         var me = this,
-            record = records.length ? records[0] : null,
             cfg;
 
         cfg = me.buildSourceConfig(record);
@@ -193,12 +192,15 @@ Ext.define('TrackEvents.form.field.UserDataMultiDefault', {
 
             // get the configuration for the Ext.grid.property.Grid
             record = combo.findRecordByValue(combo.getValue());
-            cfg = me.buildSourceConfig(record);
 
-            // fill the property grid
-            // NOTE: let the editor take care of the data type conversion
-            // when the user data block definition change
-            me.grid.setSource(value, cfg.sourceConfig);
+            if (record !== false) {
+                cfg = me.buildSourceConfig(record);
+
+                // fill the property grid
+                // NOTE: let the editor take care of the data type conversion
+                // when the user data block definition change
+                me.grid.setSource(value, cfg.sourceConfig);
+            }
         }
 
         // the standard way to set the value for a field