Index: CKEditor/trunk/_source/plugins/styles/plugin.js
===================================================================
--- CKEditor/trunk/_source/plugins/styles/plugin.js	(revision 4980)
+++ CKEditor/trunk/_source/plugins/styles/plugin.js	(revision 4991)
@@ -1192,5 +1192,5 @@
 			var temp = new CKEDITOR.dom.element( 'span' );
 			temp.setAttribute( 'style', unparsedCssText );
-			styleText = temp.getAttribute( 'style' );
+			styleText = temp.getAttribute( 'style' ) || '';
 		}
 		else