If you use Delete browsing, search and download history on Firefox in Firefox 3.5 and later or Clear Private Data in Firefox 3 to clear the 'Browsing History' when Firefox is closed then restoring tabs from the last session ("Save & Quit" or "Show my windows and tabs from last time") doesn't work.

I read the OP's question a little differently.

When you save your opened tabs upon closing Firefox, the URLs's are saved so those pages are reloaded the next time you open Firefox, but the actual content of those pages isn't saved in offline storage.

If Firefox would be able to open the tabs by knowing the URL then you would get an Offline alert that Firefox is currently offline. If Firefox doesn't give such an alert then that would indicate that the tab history got lost.

"I read the OP's question a little differently.

When you save your opened tabs upon closing Firefox, the URLs's are saved so those pages are reloaded the next time you open Firefox, but the actual content of those pages isn't saved in offline storage." This is exactly my issue .any help please !

Install the MAFF extension which allows you to "save more than one tab in a single MAFF file."

i use 3.5.10 ff browser.to read offline a web page containing text,interactive animation i follow procedure (read later).after closing and reopening offline the (html) text does not appear.using flash(Shock wave)version 10.1.53.64.op system windows xp home.

K.Venkataramani