ace-window.el (aw-dispatch-when-more-than): New defcustom

Fixes #109

ace-window.el

@@ -109,6 +109,10 @@ This will make `ace-window' act different from `other-window' for
   one or two windows."
   :type 'boolean)
 
+(defcustom aw-dispatch-when-more-than 2
+  "If the number of windows is more than this, activate ace-window-ness."
+  :type 'integer)
+
 (defcustom aw-reverse-frame-list nil
   "When non-nil `ace-window' will order frames for selection in
 the reverse of `frame-list'"
@@ -317,7 +321,7 @@ Amend MODE-LINE to the mode line for the duration of the selection."
                    (when (eq aw-action 'exit)
                      (setq aw-action nil)))
                  (or (car wnd-list) start-window))
-                ((and (= (length wnd-list) 2)
+                ((and (<= (length wnd-list) aw-dispatch-when-more-than)
                       (not aw-dispatch-always)
                       (not aw-ignore-current))
                  (let ((wnd (next-window nil nil next-window-scope)))