Index: wp-includes/js/quicktags.dev.js
===================================================================
--- wp-includes/js/quicktags.dev.js	(revision 18725)
+++ wp-includes/js/quicktags.dev.js	(working copy)
@@ -570,6 +570,7 @@
 
 	qt.closeAllTags = function(editor_id) {
 		var ed = this.getInstance(editor_id), btn = ed.getButton('close');
+		if ( typeof btn  != 'undefined' )
 		btn.callback.call(btn, '', ed.canvas, ed);
 	};