One change in Firefox 4 is to by default stop Firefox displaying the warning message, but it can be turned back on by changing some preferences.

1. Type about:config into the location bar and press enter
2. Accept the warning message that appears, you will be taken to a list of preferences
3. Locate the preference browser.tabs.warnOnClose, if its value is set to false, double-click on it to change its value to true
4. Repeat this for these 3 preferences browser.warnOnQuit, browser.warnOnRestart and browser.showQuitWarning

solved the problem ... thank you !!

Thanks, totally solved it.

This should be an option in Tools, not a code setting change. Not everyone is comfortable following these steps. You are eliminating a user group.

It solved the problem, but I agree with diamond4. This should be in the tool/option. It was in previous versions.

This is a tweak actually. Not an option open to the general users.

And to the folks who are not teach savy-
1.the location bar a.k.a the place to put in the website address.

2.having difficulty finding the 3 preferences from that scary list? No problem...Use the Filter space which is just below the "Latest Headline" tab.

Thanks, this worked for me.

First of all, thanks TonyE, thanks allot. I completely agree with diamond4. Why would this change from 3.7 to 4 anyway? This was enabled before the upgrade. No option in the menu could fix this. It sucks having to use about:config! I remember the same thing happened with an older version with open new tab behavior, where one had to change about:config to make new tabs appear next to the current one! What's all that about? Changing the small details that make us love this program!

I know this is a bit of a hassle-- and no, it shouldn't have to come to this--but for those of you who may find that following the above instructions in about:config didn't resolve the problem (like me at first): Do it once more, and after you click-out the about:config tab, close out FFox and any other open programs, and then go to the main download page for Mozilla, download and install the newest edition of Four. You'll have to reboot your PC as usual, at the end. FFox will remember all your settings and passwords, etc. Everything appeared back to normal for me after this. Finally.

Funny that "Start Private Browsing" will automatically save your tabs. LOL.