User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20080921033621 Minefield/3.1b1pre Firefox/3.0.1 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20080921033621 Minefield/3.1b1pre Firefox/3.0.1 Bug 392870 - Easy discoverability of Tabbed Browsing for new users introduced the closing of the browser when clicking on the close ("X") button of the single tab. This has "caught out" many users who were unable of this patch being landed. The adding or enabling of a dialog box to confirm the closing/exiting of the browser regardless of whether the browser is set to restore the previous browsing session would be a nice way to avoid annoying (antagonizing?) users. It would be OK if it were the same as the existing WarnOnClose and/or WarnOnQuit including having the option to disable it. Reproducible: Always Steps to Reproduce: 1. Browser with just a single tab. 2. Click on the single tab's Close ("X") Button. Actual Results: Browser closes immediately and without warning. Expected Results: A warning or confirmation dialog box should come up asking if the user wants to close the browser.

A dialog box would be almost the worst possible solution UI wise. If there should be UI, I'd rather have a "Make Firefox behave as a proper MDI application" option (with different text, of course, so that users actually have a chance of understanding it). Alternatives are a hidden pref (cf. bug 455852), or changed default behavior (either never allow to close the last tab, or only when it's blank). All of these alternatives don't interrupt the possible work-flow as badly as a prompt... -> WONTFIX To figure out the best alternative, I suggest starting a new discussion in the mozilla.dev.apps.firefox newsgroup before filing new bugs, though. BTW: The tab close button is supposed to go away when there's only one tab open, anyway, which could make this bug INVALID in a week or so.

(In reply to comment #1) > BTW: The tab close button is supposed to go away when there's only one tab > open, anyway, which could make this bug INVALID in a week or so. Does middle clicking on a tab to close the last one also stop working? Or how about the "Close Tab" menu? I think this bug is really about closing the tab, not a particular way to do it.

The pref is now there, the (x) button is gone from the last tab, that should be fine. > Does middle clicking on a tab to close the last one also stop working? Or how > about the "Close Tab" menu? I think this bug is really about closing the tab, > not a particular way to do it. Not sure I'm terribly concerned about those two cases, but if someone's interested, I *don't* think the middle click accelerator should work, and *do* think that "Close Tab" should be "Close Window" in the one-tab case.