User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5 (.NET CLR 3.5.30729) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5 (.NET CLR 3.5.30729) When only 1 tab is present and the tabs are set to 'always show' the GUI (x) to close the tab is not present. This is contrary to expected behaviour and no longer allows you to close the content of a tab (displaying about:blank) without closing the full browser or using keyboard controls. Appears properly if 2 tabs are present. Reproducible: Always Steps to Reproduce: 1. Open 2 tabs 2. Close 1 tab 3. Observe Close button (x) disappear Actual Results: No close button (x) appears Expected Results: Display close button (x)

Additional info: Also incorrectly greys out "Open in a new window" and "Close tab" in the context menu. Also breaks tear-off functionality.

I can confirm this bug. FF 3.5 on XP SP3.

This is a significant change in behavior from 3.0.x, and a very frustrating and useless one. I should NOT have to open a new tab to clear the contents of a single tab and restart that tab. I have seen several workarounds for this that involve either installing additional add-ons or modifying userChrome.css or both, but neither should be required to produce this functionality. With browser.tabs.closeButtons (the default) a close button is supposed to show on EVERY tab (http://kb.mozillazine.org/Browser.tabs.closeButtons). This includes when there is only one tab. Ot at least it has in the past and should continue to do so now. Please do not mistake this for a minor annoyance. I'm ready to downgrade back to 3.0.11 as a result, and I've seen several comments in forums this AM re people moving to other browsers. Stupid user interface tricks like this that require users to take additional steps to accomplish something they used to do in a single step are pointless annoyances.

Also, counter to expected behaviour with browser.tabs.closeButtons = 1, when more than 10 tabs exist the close button only appears on the active tab. Close buttons should still appear on all tabs and the 11th tab should be pushed outside of the visible tab area.

Today I upgraded to version 3.5.1, and am having the same problem. Firefox does not let the last tab be closed unless a 2nd tab is first opened. This problem is VERY annoying. Why was the design changed? Why should users have to open a new tab before they are allowed to close a tab?

See Bug 501714 ?

Wait.... I just discovered, under my FF3.5, a hanging outgoing message in Thunderbird. Clear that [canceling the send, then closing TBird, then using CtlAltDelete to close the remnant that was the progress bar...] -- doing all that cleared the odd behavior on FF3.5 So, I am left with this -- how can a problem in TBird cause FF to behave so oddly? Are they sharing DLL names?

1) Actually, I notice on my FF3.5.1, that although the RedX disappears on that last tab, and that -Tab's- context menu has a grayed out "Close Tab" . . . . . . There is still a functioning close tab on the FF3.5 main "File" submenu. Easily accessed, but the last tab's RedX and context menu should be fixed/restored. I am also using 3.5.30729, w/o TabMixPlus in this test. 2) I also note that odd tab behavior alluded to here [and bug 501714] is random, and not common. I can not account for that.

For those needing a fix until it's properly fixed: https://addons.mozilla.org/en-US/firefox/addon/12991

There are 2 workarounds to this problem, but both of them require the user to do extra work to close the last tab: (1) File menu --- Close Tab (2) or open a new tab, and then close the previous one Both methods require an extra click. An extra click may not seem like a lot, but it adds up over the course of a day, and quickly becomes very annoying, especially since I use the 'x' method for all the other tabs, and have to keep remembering to change to a different method for the last tab.

Thank you for the addon link. It seems to fix the problem.

I haven't tried it, but the idea that there is an add-on that fixes this is nice enough I suppose. But the fact remains that this is a documented feature that does not work properly. Browser.tabs.closeButtions = 1 (the default) is supposed to show a close button on every tab. There is and was no reason to change this behavior and require an add-in to replace replicate lost functionality. Since all that implies is that there is now more overhead. I've downgraded to 3.0.x a while back, and won't bother upgrading to 3.5.x or 3.6.x until this is fixed.

A new release of Firefox just came out (3.5.2), but the bug is still there. The close button is still missing from the last tab. Why is Mozilla refusing to fix this bug? How difficult could it be to fix? After all, it was working in all previous versions. Unfortunately, the Add-on that added the close button was causing other problems with tabs, so I had to remove it. (With the add-on installed, right-clicking on links to open new tabs would stop working.)

Build worked : Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20080929033431 Minefield/3.1b1pre Build broken : Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20080930050845 Minefield/3.1b1pre

Dao, is that bug a wontfix now?

Bug 501714 adds back the close button for browser.tabs.closeWindowWithLastTab=false.