(defvar my-fullscreen-p t "Check if fullscreen is on or off")

(defun my-non-fullscreen ()
  (interactive)
  (if (fboundp 'w32-send-sys-command)
      ;; WM_SYSCOMMAND restore #xf120
      (w32-send-sys-command 61728)
    (progn (set-frame-parameter nil 'width 82)
           (set-frame-parameter nil 'fullscreen 'fullheight))))

(defun my-fullscreen ()
  (interactive)
  (if (fboundp 'w32-send-sys-command)
      ;; WM_SYSCOMMAND maximaze #xf030
      (w32-send-sys-command 61488)
    (set-frame-parameter nil 'fullscreen 'fullboth)))

(defun my-toggle-fullscreen ()
  (interactive)
  (setq my-fullscreen-p (not my-fullscreen-p))
  (if my-fullscreen-p
      (my-non-fullscreen)
    (my-fullscreen)))

(global-set-key [(f11)] 'my-toggle-fullscreen)
;(run-with-idle-timer 0.1 nil 'my-toggle-fullscreen)
;(my-toggle-fullscreen)