Index: /CKEditor/trunk/_source/plugins/dialog/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/dialog/plugin.js	(revision 7040)
+++ /CKEditor/trunk/_source/plugins/dialog/plugin.js	(revision 7041)
@@ -295,5 +295,5 @@
 						{
 							var retval = item.validate( this ),
-								isValid = retval === true ;
+								isValid = retval !== false ;
 
 							if ( !isValid )