diff --git a/thirdparty/multifile/multifile.js b/thirdparty/multifile/multifile.js
index 99a68a81..cfe2e6ef 100755
--- a/thirdparty/multifile/multifile.js
+++ b/thirdparty/multifile/multifile.js
@@ -182,7 +182,8 @@ function MultiSelector( list_target, max, upload_button ){
 		this.list_target.appendChild( new_row );
 		
 		// Modified 2006-11-06 by Silverstripe Ltd.
-		window.ontabschanged();
+		console.debug(typeof(window.ontabschanged));
+		if(typeof(window.ontabschanged) != 'undefined') window.ontabschanged();
 		
 	};