Hazlo on "[Plugin: Autoptimize] Excluded Scripts don't work in Some Browsers"

Hello,
I use Autoptimize together with the Lite Cache plugin and this combination makes my site loading time much much faster.
I have enabled html, js, and css optimization.
I only excluded two scripts from the js optimization in order to let them work : "shadowbox", and "Custom Contact Form".
Since then everything works good except the Contact Form which is OK on some browsers (Chrome, Safari) but whose behavior is funny with Firefox: the text telling the visitors that their message was successfully sent does not pop up as it should. So people don't know if the message was really sent or not.
I really wonder why this trouble only comes with Firefox? (the Form works good again if deactivating Autoptimize). I guess I mentioned it right (in the excluded js box), because if not it would not work at all, with any browser.
Any idea to fix it?
Thanks a bunch. In advance.

http://wordpress.org/extend/plugins/autoptimize/