Saveguard doesn't work with the browser's back button

I've installed this modules because in Firefox for OS X the Cmd+Left-Arrow combination corresponds to the back button, while in most of the other applications it is used to go back one word while editing some text. You can imagine why I'd like to be blocked when the browser tries to go back one page...

Unfortunately Saveguard doesn't help with that, I'm silently moved back to the previous page and I loose all the content and I get angry and I scream as usually... I really wish this can be fixed.