diff --git a/date_elements.inc b/date_elements.inc
index 7abf956..764e8cb 100644
--- a/date_elements.inc
+++ b/date_elements.inc
@@ -637,7 +637,7 @@ function date_empty_end_date(&$element, &$form_state, &$input) {
   $parent = array_pop($parents);
   if ($parent == 'value2') {
     $parent_values = drupal_array_get_nested_value($form_state['values'], $parents);
-    if (isset($parent_values['show_todate']) && $parent_values['show_todate'] != 1) {
+    if (isset($parent_values['show_todate']) && $parent_values['show_todate'] === 0) {
       $input = array();
       form_set_value($element, NULL, $form_state);
     }