With self-built 112, folders under [Gmail] display one level up. For example

A
B
[Gmail]
  A
  B
C

displays as

A
B
A
B
C

The unselectable [gmail] folder does not display at all. So it looks like I have folders at the same level with duplicate names.

We removed that ghost [Gmail] folder on purpose to make the folder pane behave more consistently across providers.
I don't see any duplicate folders, what are those?
Are those special folders like Trash or Drafts with proper icons?
How are those folders represented in Gmail?
Did you create those folders, or previously moved them outside the ghost [Gmail] folder, or maybe another program created them automatically?

They are not really duplicate folders, just folders with the same name at different levels.
I had created the folders myself months or years ago just for test purposes. I don't remember why. They currently have different content.

At gmail they show up as labels like:

gds
[Gmail]/gds

But when the "ghost" folder [Gmail] is gone from TB 112 they appear as two folders at the same level with the same name gds but with different content which looks like something is wrong even if it's not.

The workaround to only see folders under [Gmail] and hide the ghost has been to set the advance server setting "Imap server directory" to [Gmail] but it hides the folders at the same level as [Gmail] but you don't see possible duplicate folder names.

https://searchfox.org/comm-central/rev/0f29df3556018ea0dbbb4d6c862f06a26d8f9209/mail/base/content/about3Pane.js#989-991

Note that there is also [Google Mail], and I'm assuming translated versions of it as well? https://bugzilla.mozilla.org/attachment.cgi?id=9319229

My gmail accounts - on a windows system account "A" I see two Trash folders, both with the "special" icon. And on Mac with account "B" I see two trash and two Sent, all with the "special" icon.

I see extra folders in 110 beta, but I didn't manually create the extras in either example - I assume they were created by an iphone or older instance of Thunderbird.

My gmail accounts - on a windows system account "A" I see two Trash folders, both with the "special" icon.

That's another regression of mailnews.imap.jsmodule=true. I filed bug 1818589 for that.

https://searchfox.org/comm-central/rev/0f29df3556018ea0dbbb4d6c862f06a26d8f9209/mail/base/content/about3Pane.js#989-991
Note that there is also [Google Mail]

Will this be handled in this Bugzilla ticket as well or is there another one for this / should be filed? Since I am affected by this I want to know where I have to follow. :)

I think this is a WONTFIX if it was caused by manual creation of folders.

This could result in surfacing hidden folders that people or apps had created previously and users didn't realize were there, though. I'm not really sure if that's a problem we can solve or how widespread it might be.

Not sure why but my gray [Gmail] imap folder is back with a self-build C-C with tip at 38480:7b52c222b4a0, which, to me, is good. I don't think the folder structure that users are used to seeing should change spontaneously.

Think it was changed in bug 1818592.

Ok, pulled in the latest C-C and now I'm NOT seeing the [Gmail] unselectable subfolder again. And, as originally noticed, I see folders at the same level with identical names but with different content.

Also, when I look at subscribe (right-click dialog), I still see the gray folder [Gmail] (not subscribable) and I see the sub-folders under it that are promoted up a level in the newest folder tree view.

I think this new gmail flat folder tree view should be made a user selectable setting that defaults to the current (v102) view showing [Gmail] and its sub-folders to avoid possible folders with the same name at the same level. Also, maybe not a good idea to change the gmail folder view that most users are now used to.

(In reply to Andrei Hajdukewycz [:sancus] from comment #8)

I think this is a WONTFIX if it was caused by manual creation of folders.

This could result in surfacing hidden folders that people or apps had created previously and users didn't realize were there, though. I'm not really sure if that's a problem we can solve or how widespread it might be.

My folders with the same name were not "hidden" and I did realize they were there.

We want to keep the flat folder hierarchy and ignore the [Gmail] ghost folder.
Marking this as WONTFIX, but if there are other problems, like missing folders or incorrect hierarchy, please open another dedicated bug.

If this is not a bug then it at least needs a release note telling users that they may see folders with the same name at the same level, as illustrated in comment 0.
Also, the subscribe dialog still shows [Gmail] folder and the folders under it. Not sure if subscribe dialog should be "flat" too.

(In reply to Alessandro Castellani [:aleca] from comment #12)

We want to keep the flat folder hierarchy and ignore the [Gmail] ghost folder.
Marking this as WONTFIX, but if there are other problems, like missing folders or incorrect hierarchy, please open another dedicated bug.

Please read bug 1835891
It refers to beta 116*
Creating a imap gmail account creates non imap pop type files which obviously are not server folders and never display, but they get created an put into imap.gmail.com profile folder. They have to manually deleted from profile after creating imap gmail mail account.
With the exception of Inbox, all folders/files get stored in a [Gmail].sbd folder which is in imap.gmail.com - not wanted as it causes display problems eg: Subfolders do not get displayed under the correct folder as a duplicate NoSelect italic folder is created for them which is not wanted. All top level files/folders should be in imap.gmail.com but I only get Inbox plus a load of files that are not even imap files.

Set 'IMAP server directory : [Gmail]' - this is left blank by default and therefore causes a display problem, so after creating account you have to set this setting and restart which gets rid of the NoSelect folder, but then subfolders appear as top level folders despite profile folders now fully corrected - This sounds like the issue mentioned for this bug.

Then you perform another restart without needing to do anything and finally the Folder Pane respects what is in the profile folders.

As part of creating a gmail mail account, I do feel it should not be necessary to delete incorrectly created files, modify Imap server directory to get rid of [Gmail].sbd and restart several times just to get a correct set of files in Profile and a correct display in Folder Pane.

Full details of bug 1835891 includes some images showing what is going on.