Right clicking a tab offers "Save All Tabs for Later". There is no way to use on Next Session. No FAQ's, etc.
When you Right Click on an Open Tab one of the Options is "Save All Tabs for Later". There are No further prompts. You close the current session and Open a new Session and there is no Prompt to "reopen" those [supposedly] saved sites. All data is lost.
Wšě wotmołwy (2)
That is not a built-in option for Firefox. Do you have the Read It Later extension, that option appears to be added by that extension.
For help with that extension see http://readitlaterlist.com/help/
I had the same problem, you need to deleted the saved page from Read-It-Later. Click on the "T" in bottom right of Firefox, it leads you to the saved page. Uncheck the red check mark on Address Bar. That's all.
The Read-It-Later website also tells you how: http://ideashower.com/support/read-it-later/how-to-delete-an-item-from-your-reading-list/
Go to back that website again, the "T" thing should be gone now.
Wot colstat změnjeny