Index: core/kernel/utility/formatters/formatter.php
===================================================================
--- core/kernel/utility/formatters/formatter.php
+++ core/kernel/utility/formatters/formatter.php
@@ -210,7 +210,7 @@
 	public function Parse($value, $field_name, &$object)
 	{
 		if ($value == '') {
-			return NULL;
+			return $value;
 		}
 
 		$options = $object->GetFieldOptions($field_name);