Is there a reason why you don't use FF57.0.4 or releases instead of using beta or test versions?

I don't know, I've been using Firefox Quantum since September. At this time, It was under beta version. The browser just updated itself from this moment and I finally got 58b16. Do you think It comes from this ?

Not mine that I recall it tells me but I go and offline download FF to install instead. I would if I was you get FF57.0.4 and try to reinstall it again and see if the problem comes back.

https://ftp.mozilla.org/pub/firefox/releases/57.0.4/

not sure what version you have but make sure if you have 32bit get the 32bit and if 64bit get the 64bit version. And before installing check your version right now and see if it is 32bit or 64bit so you get the right version.

"External software" will use the Default browser as set in the Operating System AND use the Default Profile as was set within Firefox via the Profile Manager. And since the Developer Edition automatically creates a 2nd Profile you may be running Firefox while using the non-Default Profile and thus a 2nd Profile may be opening that new window.

So yes, using the Beta version (which is also the Developer Edition now, they were merged last year) might be the cause. If you aren't using Beta to specifically "test" the Beta version it might be worthwhile to uninstall that Beta version and install the Release version of Quantum, which came out mid-November 2017.

WestEnd said

Not mine that I recall it tells me but I go and offline download FF to install instead. I would if I was you get FF57.0.4 and try to reinstall it again and see if the problem comes back. https://ftp.mozilla.org/pub/firefox/releases/57.0.4/ not sure what version you have but make sure if you have 32bit get the 32bit and if 64bit get the 64bit version. And before installing check your version right now and see if it is 32bit or 64bit so you get the right version.

The better link to post for current Firefox 57.0.4 Release www.mozilla.org/firefox/all/

the-edmeister said

"External software" will use the Default browser as set in the Operating System AND use the Default Profile as was set within Firefox via the Profile Manager. And since the Developer Edition automatically creates a 2nd Profile you may be running Firefox while using the non-Default Profile and thus a 2nd Profile may be opening that new window.

But I do have my Firefox Developer Edition 58.0b16 browser (let's call it FDE) opened while clicking the link from an external software. The event triggers the opening of a new window (not tab like it usually does when I click from within the browser). This new window is empty and doesn't get my profile loaded (e.g. no pinned tab).

the-edmeister said

So yes, using the Beta version (which is also the Developer Edition now, they were merged last year) might be the cause. If you aren't using Beta to specifically "test" the Beta version it might be worthwhile to uninstall that Beta version and install the Release version of Quantum, which came out mid-November 2017.

In fact, I don't mind using a non-beta version, I just want to get FDE with the default dev's settings. By any chance, is there any stable FDE ?

WestEnd said

Not mine that I recall it tells me but I go and offline download FF to install instead. I would if I was you get FF57.0.4 and try to reinstall it again and see if the problem comes back. https://ftp.mozilla.org/pub/firefox/releases/57.0.4/ not sure what version you have but make sure if you have 32bit get the 32bit and if 64bit get the 64bit version. And before installing check your version right now and see if it is 32bit or 64bit so you get the right version.

You were right. I tried with Firefox 57.0.4 (non-dev version) and all goes like a charm. It worked before so it seems obvious the issue is caused by the version of my browser. I think It happened between FDEb14-b16.

So, should I use the classic Firefox ? I like to get the latest features, test, send infos/data/feedbacks. And, by experience, FDE is significantly better to code and the settings look great. But I don't know the exact differences.

Yes, I know you are using Firefox 58 Beta/FDE by your UserAgent near the top of the right-hand column; this forum reads the UA string that is "broadcast" to every website you visit to help the website format their content for particular web browsers.

1. Are you sure FDE is using the same Profile in the second window as you were using in the first? You can open about:profiles (Type that in the URL bar and hit Enter - in both windows) and look for This is the profile in use and it cannot be deleted which is the Profile being used in each respective window.
2. Beta and FDE are now combined and technically it isn't "stable", plus it is updated many times over the 6 weeks when Beta is being tested before it becomes the next Release version of Firefox. "Stuff" breaks every now and then, and sometimes new features are pulled because those features aren't just quite ready for Release, which happened this week with the new Form Filler feature which not every Beta/FDE had even seen yet. It was being rolled out to a small number of users for testing, which started with 57 back in November.
3. Sorry, there is nothing that is labeled as "classic" Firefox. The development channels are Nightly (alpha development with daily or twice daily updates)' for 6 weeks, Beta/FDE for another 6 weeks (with 12 to 16 updates), then Firefox is Released (57 got 4 bug fix updates and two major security fixes in 57.0.4) which is another 6 week span until the next Release version comes out. Although at the end and beginning of each year there is an 8 or 9 week length on all channels, which is currently 57 Release, 58 Beta/FDE, and Nightly 59. And only Release should be considered "stable".

Basically all three channels are Firefox, at the alpha, beta, and release stages of the development process and they "jump up" a notch every 6 weeks as they go thru the 3 stages.

To solve your issue with an external application opening what may be a different Profile, you should identify the Profile being used in each window. If they are different we will know why that issue is occurring.

If you don't understand what I am talking about with Profiles, maybe the Release version would be better for you to be using.

As far as actual "developer" features, the Release versions have had as much as the Beta/FDE has had recently. The only real thing that is lacking is the multiple Profiles being created; 1 upon installation and the 2nd the first time Beta/FDE is used, as I recall. And that may be what is involved in this external application "thing".

The only other thing is to wait until later today when a contributor with more specific Linux knowledge is around. Firefox I know well, but my experience with Linux OS's is limited. I may be missing something - but at least check out if both windows are using different Profiles or just one and something that didn't occur to me is "off".

the-edmeister said

Yes, I know you are using Firefox 58 Beta/FDE by your UserAgent near the top of the right-hand column; this forum reads the UA string that is "broadcast" to every website you visit to help the website format their content for particular web browsers.

Oh right, I didn't notice this menu, that's smart.

1. Are you sure FDE is using the same Profile in the second window as you were using in the first? You can open about:profiles (Type that in the URL bar and hit Enter - in both windows) and look for This is the profile in use and it cannot be deleted which is the Profile being used in each respective window.

So I did It and the interesting thing is that the two windows have the exact same current profile loaded.

1. Beta and FDE are now combined and technically it isn't "stable", plus it is updated many times over the 6 weeks when Beta is being tested before it becomes the next Release version of Firefox. "Stuff" breaks every now and then, and sometimes new features are pulled because those features aren't just quite ready for Release, which happened this week with the new Form Filler feature which not every Beta/FDE had even seen yet. It was being rolled out to a small number of users for testing, which started with 57 back in November.

Thanks for the detailed explanation, I understand better now. By the way, I've been looking for this kind of feature (form filler) for a long time. That's really great to know It will come pretty soon.

1. Sorry, there is nothing that is labeled as "classic" Firefox. The development channels are Nightly (alpha development with daily or twice daily updates)' for 6 weeks, Beta/FDE for another 6 weeks (with 12 to 16 updates), then Firefox is Released (57 got 4 bug fix updates and two major security fixes in 57.0.4) which is another 6 week span until the next Release version comes out. Although at the end and beginning of each year there is an 8 or 9 week length on all channels, which is currently 57 Release, 58 Beta/FDE, and Nightly 59. And only Release should be considered "stable".

Basically all three channels are Firefox, at the alpha, beta, and release stages of the development process and they "jump up" a notch every 6 weeks as they go thru the 3 stages.

Alright. Does It mean FDE is only made for Firefox/Add-on developers, not all developers ? That what I've thought.

To solve your issue with an external application opening what may be a different Profile, you should identify the Profile being used in each window. If they are different we will know why that issue is occurring. As far as actual "developer" features, the Release versions have had as much as the Beta/FDE has had recently. The only real thing that is lacking is the multiple Profiles being created; 1 upon installation and the 2nd the first time Beta/FDE is used, as I recall. And that may be what is involved in this external application "thing".

They aren't different, they're definitely the same.

If you don't understand what I am talking about with Profiles, maybe the Release version would be better for you to be using.

That's ok, I get it, no problem.

The only other thing is to wait until later today when a contributor with more specific Linux knowledge is around. Firefox I know well, but my experience with Linux OS's is limited. I may be missing something - but at least check out if both windows are using different Profiles or just one and something that didn't occur to me is "off".

It should be good to discuss with one of them, you're right. But I think this is not the issue, here. See bellow to understand why I'm wondering it :

1. I open FDE
2. I set It as my default browser with a displayed banner (to get the web links opened by this version)
3. I click on a link found in one of my inbox email in Thunderbird (same behaviour with other instant chat softwares..)
4. I get a new FDE window with the exact same version (I used to get other versions maybe still installed somewhere on my computer)
5. If I check the about:profiles tab in both FDE instances, I get the exact same profile used
6. As a reminder, the newly opened window is empty, just getting some "suggestion cards" about my last visited pages

Then,

1. I close FDE
2. I open Firefox 57.0.4
3. I set it as my default browser
4. I click on the exact same links as mentioned above in the same softwares and boom, all of the links are opened in the window I ran just before.

It doesn't seem to be a Linux nor a profile problem. Could It be an bug introduced in FDEb15 or 16 ?

I'm stumped now, with my theory about different Profiles being wrong.

Wait until later in the day when a couple of Linux using contributors show up here, one of them will probably have a better idea what could cause that.

Sorry, I gave it a shot.

Are you starting Firefox with the -no-remote command line switch in case that could matter?

Is the %u parameter (Exec=firefox %u) present in the .desktop file to pass the URL to Firefox?

Indeed, you were spot on. I didn't use the -no-remote flag but the %u parameter was missing. I used to install Firefox with apt or umake. These tools provided a clean installation.

But this time, I wanted to get the last FDE version, so I did it by myself. I didn't know about the %u parameter and its use.

Now It's working like a charm. It could help other Firefox users. Thanks a lot ! Thank to the-edmeister for trying so hard to help me and for your complete infos about Firefox.