bug#59721: 30.0.50; tab bar groups are not ordered properly

[Juri Linkov]

> I did not check if that solves it, but this issue --
> and how I discovered it -- manifests itself when you use
> `display-buffer-in-[new]-tab' and set a tab group that way.
>
> This can result in a large amount of distinct tab group entries for
> the same tab group; does `tab-bar-tab-post-change-group-functions'
> also resolve this?

Your guess is right.  After customizing this variable and using e.g.

(add-to-list 'display-buffer-alist
             '("buffer1" .
               (display-buffer-in-tab
                (tab-name . "C")
                (tab-group . "foo"))))

it merges the new tab with its group.

> Because just about anybody who'd use said display buffer action would
> find themselves in this predicament and that variable (and
> subsequently adding that function to it) is... unintuitive.

So you suggest to make this value the default?  Ok, the default value
will be changed in the release branch.