Index: typo3/sysext/cms/layout/res/grideditor.js
===================================================================
--- typo3/sysext/cms/layout/res/grideditor.js	(revision 10213)
+++ typo3/sysext/cms/layout/res/grideditor.js	(working copy)
@@ -158,7 +158,7 @@
 			border: '0',
 			width: '100%',
 			height: '100%',
-			class: 'editor',
+			'class': 'editor',
 			cellspacing: '0',
 			cellpadding: '0'
 		};