diff --git a/code/GridFieldBulkEditingTools.php b/code/GridFieldBulkEditingTools.php
index f19fc32..af30961 100644
--- a/code/GridFieldBulkEditingTools.php
+++ b/code/GridFieldBulkEditingTools.php
@@ -8,9 +8,8 @@
 class GridFieldBulkEditingTools {
 	//put your code here
 	
-	public static function getModelDataFields ( $gridfield )
+	public static function getModelDataFields ( $modelClass )
 	{
-		$modelClass = $gridfield->list->dataClass;
 		$cmsFields = singleton($modelClass)->getCMSFields();
 		$fields = $cmsFields->dataFields();