Now that I've upgraded, everytime I quit Firefox it no longer prompts whether I want to save my tabs before quiting. How do I get this setting back?

Plz check the attachment. And check the option to warn you when closing multiple tabs.

Firefox 4 saves the previous session automatically, so there is no longer need for the dialog asking if you want to save the current session.<br /> You can use "Firefox > History > Restore Previous Session" to get the previous session.<br /> There is also a "Restore Previous Session" button on the default <b>about:home</b> Home page. Another possibility is to use: * [http://kb.mozillazine.org/Menu_differences Firefox > Preferences] > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time" Make sure that you do not use [[Clear Recent History]] to clear the 'Browsing History' when you close Firefox.