If you use Delete browsing, search and download history on Firefox in Firefox 3.5 and later to clear the 'Browsing History' when you close Firefox then restoring tabs from the last session ("Save & Quit" or "Show my windows and tabs from last time") doesn't work.

I do not use Tools / Clear Recent History. I do not know where to find the "Save & quit", I only have File / Exit

here is how I've set a few options that seem relevant

Tools / Options / General / When Firefox starts: [Show my windows and tabs from last time]

Tools / Options / Privacy / History

                                Firefox will [Use custom settings for history]

that one I might have changed from [Remember history]; with Remember history I think there is no way to block third party cookies, right?

                                [Automatically start Firefox in a private browsing session]    NOT checked
                                [Clear history when Firefox closes]  NOT checked

whoops, I didn't mean to be dense about save & quit. I can restore content to a tab from a local copy if I Ctl-S save, and then Exit. But I think 6 months ago I did not have to save before closing firefox; the next time I opened it the tabs would be restored WITH their content. Now the tabs are restored with their URLs, but the content is gone, it must be downloaded again.