You do not get the 'Save & Quit' pop-up dialog if you choose Tools > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time".

If that option is selected then your pages will already be reopened the next time.
To get that pop-up dialog you have to select one of the other choices (Show my home page or Show a blank page).

You can set the warn prefs on the about:config page to true via the right-click context menu or toggle the value with a double left-click.

• browser.showQuitWarning, see http://blog.zpao.com/post/3174360617/about-that-quit-dialog
• browser.tabs.warnOnClose, see http://kb.mozillazine.org/About%3Aconfig_entries
• browser.warnOnQuit , see http://kb.mozillazine.org/browser.warnOnQuit
• browser.warnOnRestart , see http://kb.mozillazine.org/browser.warnOnRestart

• http://kb.mozillazine.org/about:config

Hi, my issue has nothing to do with saving tabs for the next time. If I have at least two tabs open, then click on the X to close the window, I do not want the window and tabs to close. I want a warning asking me, "do you want to close this window?"

That feature is not working anymore. It just closes the window without prompting a warning, asking if that is what I really want to do.

In About:config find browser.warnOnQuit and double-click on it top make it TRUE.

Do the same with browser.tabs.warnOnClose

thank you

Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

EDIT cor-el sorry you already suggest, what i suggest, 1 day ago !

where i had my mind ? sorry again

Quote: "In About:config find browser.warnOnQuit and double-click on it top make it TRUE. Do the same with browser.tabs.warnOnClose"

Both of these settings were already set to True. This does not help.

Thanks, Jamie

I checked another machine with Windows 7 professional and the warning box appears before allowing me to close.

On the XP machine, the warning still does not appear. I can have 1,2,5, or more tabs open and if I click on the X to close, they all disappear instantly.

Are there any other windows (Library, Download manager) open when this happens?

No. All I have open or running is a single FireFox window with multiple tabs open.

Try to reset the preferences.

• https://support.mozilla.org/kb/Resetting+preferences
• http://kb.mozillazine.org/Resetting_preferences

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Yes! When I reset the preferences, the warning came back. Thank you.

Update - NOT solved. Sorry. The warning did come back, but as soon as I went to private browsing and asked 'not to be tracked', the warning went away and the windows closed without warning.

So, the warning does not work in private browsing.

I also have this problem when private browsing is selected. I noticed that if two instances of FF 13.0.1 are running the warning about closing multiple tabs is shown. If only one instance is running, no warning about closing multiple tabs is shown. If private browsing is not selected warning shows as expected.

This exact bug is back in FF17, even if private browsing is not selected.

Update: setting browser.warnOnQuit to true now does the trick and brings browser.tabs.warnOnCloseOtherTabs back to functionality again.