When I click on the icons in the near of the window title sometimes the
menus hang and I got on terminal "Menu already active" when I try to open a
window menu.

I don't know much about (I think lisp), but the error is maybe in
sawmill/lisp/sawfish/wm/menus.jl:
(define (popup-menu spec)
(or spec (error "No menu given to popup-menu"))
(if (and menu-active menu-process (process-in-use-p menu-process))
(error "Menu already active")
(let* ((part (clicked-frame-part))
(offset (and part (frame-part-position part)))
(dims (and part (frame-part-dimensions part))))
(setq menu-active (or (current-event-window) (input-focus)))
(condition-case error-data
(progn
(menu-start-process)
;; prevent any depressed button being redrawn until the menu
;; is popped down
;; XXX expose events screw this up..
(when (clicked-frame-part)
(frame-draw-mutex t))
;; This function is probably called from a ButtonPress event,
;; so cancel the implicit pointer grab (to allow the menu's grab
;; to succeed)
(ungrab-pointer)
(ungrab-keyboard)
(sync-server)
(when (functionp spec)
(setq spec (spec)))
;; XXX this is a hack, but I want menus to appear under buttons
(if (and part (setq part (frame-part-get part 'class))
(windowp menu-active)
(string-match "-button$" (symbol-name part)))
(progn
(rplaca offset
(max 0 (+ (car offset)
(car (window-position menu-active)))))
(rplacd offset
(max 0 (+ (cdr offset) (cdr dims)
(cdr (window-position menu-active))))))
(setq offset nil))
(setq nickname-table (make-table eq-hash eq))
(setq nickname-index 0)
(format menu-process "(popup-menu %s %S %S)\n"
;; write out the menu spec in one chunk to
;; avoid large numbers of system calls :-[
(format nil "%S" (mapcar menu-preprocessor spec))
(x-server-timestamp) offset))
(error
;; prevents spurious errors with subsequent menus
(setq menu-active nil)
(apply signal error-data))))))