Index: /trunk/source/cocoa-ide/cocoa-editor.lisp
===================================================================
--- /trunk/source/cocoa-ide/cocoa-editor.lisp	(revision 12915)
+++ /trunk/source/cocoa-ide/cocoa-editor.lisp	(revision 12916)
@@ -2576,9 +2576,5 @@
                                (lisp-string-from-nsstring
                                 (#/displayName doc))
-                               :modes '("Lisp" "Editor"))))
-      ;; Cocotron's NSUndoManager implementation causes CPU usage to peg at 90+%
-      ;; Remove this when Cocotron issue #273 is fixed
-      ;;  (http://code.google.com/p/cocotron/issues/detail?id=273)
-      #+cocotron (#/setHasUndoManager: doc nil))
+                               :modes '("Lisp" "Editor")))))
     (with-slots (encoding) doc
       (setq encoding (or (get-default-encoding) #$NSISOLatin1StringEncoding)))