Index: wp-includes/js/autosave.dev.js
===================================================================
--- wp-includes/js/autosave.dev.js	(revision 18646)
+++ wp-includes/js/autosave.dev.js	(working copy)
@@ -241,6 +241,10 @@
 			if ( 'mce_fullscreen' == ed.id || 'wp_mce_fullscreen' == ed.id )
 				tinyMCE.get('content').setContent(ed.getContent({format : 'raw'}), {format : 'raw'});
 			tinyMCE.triggerSave();
+			ed.isNotDirty = true;
+			ed.onChange.add( function(){ 
+				ed.isNotDirty = false;
+			});
 		}
 	}