A patch for overlay support of ac-disable-faces.

overlay.diff

--- /cygdrive/c/Emacs/site-lisp/auto-complete/auto-complete.el	2013-02-10 21:25:46.000000000 +0900
+++ auto-complete.el	2013-02-25 20:36:40.780375000 +0900
@@ -1619,7 +1619,7 @@
 ;;;; Auto complete mode
 
 (defun ac-cursor-on-diable-face-p (&optional point)
-  (memq (get-text-property (or point (point)) 'face) ac-disable-faces))
+  (memq (get-char-property (or point (point)) 'face) ac-disable-faces))
 
 (defun ac-trigger-command-p (command)
   "Return non-nil if `COMMAND' is a trigger command."