Fixes #1236 Workflows problem with Documents module "has changed to" filter condition

modules/Settings/Workflows/models/Field.php

@@ -61,7 +61,7 @@ class Settings_Workflows_Field_Model extends Vtiger_Field_Model {
 	 */
 	public static function getAdvancedFilterOpsByFieldType() {
 		return array(
-			'string' => array('is', 'is not', 'contains', 'does not contain', 'starts with', 'ends with', 'has changed', 'is empty', 'is not empty'),
+			'string' => array('is', 'is not', 'contains', 'does not contain', 'starts with', 'ends with', 'has changed', 'has changed to', 'has changed from', 'is empty', 'is not empty'),
 			'salutation' => array('is', 'is not', 'contains', 'does not contain', 'starts with', 'ends with', 'has changed', 'is empty', 'is not empty'),
 			'text' => array('is', 'is not', 'contains', 'does not contain', 'starts with', 'ends with', 'has changed', 'is empty', 'is not empty'),
 			'url' => array('is', 'is not', 'contains', 'does not contain', 'starts with', 'ends with', 'has changed', 'is empty', 'is not empty'),