Hi robtoe, how were you closing the non-audio window? For example:

• click the X button at the upper right of the window
• using Exit from the menu
• some other method

What method do you use to start a separate instance of Firefox?

Hi - I use the "X" for the non-audio window, and launch all instances of FF via Start -> Most Used (Win 10).

Usually if you use the same shortcut to launch multiple Firefox windows, they are all part of the same instance/session. You actually need to use a couple command line parameters to start independent instances/sessions of Firefox.

But I thought the "X" button just closed the current window of Firefox, not all windows of Firefox. That hasn't changed for me in Firefox 63 on Windos 7. Maybe it's a Windows 10 thing?

Assumed they were separate instances.

In any event, closing the browsing session/window does not close the audio session/window, so there shouldn't be a warning message about it.

Also, as mentioned, this started occurring today, immediately after the update. Did not occur over the several years I've been using FF.

Hmm, I can't replicate it. Mine just says "two tabs" like normal when I click the "X". Hopefully another Windows 10 user can see whether it has changed on theirs.

Thanks for the help, but we may have gotten sidetracked: there should be no message offered in this scenario.

If 2 FF windows are open, closing one of them does not affect the other. There is no need to throw a warning message about something that will not occur.

I would have suggested that FF had become unable to differentiate between windows and tabs under 63.0, however - at least on Win10 - the messaging actually mentions both.

In your testing, I'm a bit suspicious of a bug as well. You're saying you have 2 FF windows open, and closing 1 window also closes the other? If so, FF cannot differentiate between a tabbed session and windowed (which I'd be surprised by). Otherwise, if closing one window does not affect the other, you seeing the same superfluous message, mentioned in my bug.

[And yes, I could uncheck the tab closing warning, but it has saved me a few times. I just don't want to see it when it does not apply.]

No, mine has the default behavior:

• I have two windows open, with two tabs each
• Click X in one window, get the "two tabs" warning, no reference to two windows
• Proceeding closes only that window

No changes from normal Firefox behavior of recent years.

I'm referring to closing a window with only 1 tab, yet getting the multi-tab warning.

Here's the repro:

1. Using a single tab only, head to sportsnet.ca/590/, choosing to "Listen Live". 2. FF "mini player launches" in separate window. 3. Close original FF window.

Result: Get "tab closure warning". Expect: No message. (As with pre 63.0.) Detail: Closing the main FF window does not impact the player window. No warning required.

4. Launch another FF window, with player window still streaming. 5. Use only a single tab for browsing, close this window.

R - E - D is same as after step 3. No closure warning required.

This is a minor annoyance, and I've since turned off the multi-tab warning, but should not have to. This is new behaviour with 63.0.

Gist: don't warn for no reason.

Hi robtoe, okay, I see the pattern here:

Here's the repro:

1. Using a single tab only, head to sportsnet.ca/590/, choosing to "Listen Live".
2. FF "mini player launches" in separate window.
3. Close original FF window.

Result: Get "tab closure warning".
Expect: No message. (As with pre 63.0.)

Start with a single window and load the above page, or this test page: https://www.jeffersonscher.com/res/popit.html

Click the player link to launch a pop-up window with restricted features --

window.open(web_player_url, 'ListenLiveWindow', 'width=' + _this.web_player_width + ',height=' + _this.web_player_height + ',status=0,scrollbars=0,resizable=0');

-- or the third link on the test page.

Click the X button on the main window and get the attached bizarre message.

This message would only make sense if the pop-up was a dialog window that automatically closes with the main window. Since it stays open, the message does not make sense.

Exactly. Prior to 63.0 the warning did not appear in that scenario.

No biggie, as I've disabled the multi-tab warning, but one day it will burn me when I accidentally close a multi-tab window in error.  :)

It seems easier to put up with the erroneous message than to go without protection, but that's up to you.

I filed a bug report: https://bugzilla.mozilla.org/show_bug.cgi?id=1502179

My use case involves launching and closing that separate FF window dozens of times a day.