I need Firefox to ask confirmation before quitting, even if only one tab is opened. Now, if I have two tabs opened, Firefox ask for confirmation, but if have only one tab the application is closed without warning.

I've these prefs: browser.sessionstore.warnOnQuit true browser.tabs.warnOnClose true browser.tabs.warnOnCloseOtherTabs true browser.tabs.warnOnOpen true browser.warnOnQuit true