Yes, you're right!
I used that code in css(transform: translate3d...) because in the previous version of firefox, using parameter background-attachment:fixed makes certain portions of the site to disappear on scrolling. Now, with thge latest more flexible version of FF, that parameter is no longer necessary. And surely, I will use the latest version of the swfObject Reloaded whether I will use it directly included in my theme, or not.
Thanks again!