diff --git a/conditional_fields.module b/conditional_fields.module
index 03d73fa..be015a9 100644
--- a/conditional_fields.module
+++ b/conditional_fields.module
@@ -472,17 +472,21 @@ function conditional_fields_entity_view_alter(&$build, $type) {
 function conditional_fields_evaluate_dependency($options, $form_values) {
   if ($options['values_set'] == CONDITIONAL_FIELDS_DEPENDENCY_VALUES_SET_SINGLE) {
     if (is_string($form_values)) {
-      return count($options['value'] == 1) && $options['value'][0]['value'] === $form_values;
+      $form_values = $form_values == '_none' ? '' : $form_values;
+      return count($options['value']) == 1 && $options['value'][0]['value'] == $form_values;
     }
 
-    // PHP 5 compares arrays recursively.
+    // PHP 5 compares arrays recursively.    
     return $options['value'] === $form_values;
   }
 
   // Flatten array of values.
   $values = array();
   foreach ((array) $form_values as $value) {
-    $values[] = array_shift($value);
+    $value = (array) $value;
+    $value = array_shift($value);
+    $value = $value == NULL ? '_none' : $value;
+    $values[] = $value;
   }
 
   switch ($options['values_set']) {