I want to create a forum with 3 main topics:

1/ Books (new container) 2/ General Discussion (already created as forum, not container) 3/ Music (another new container)

I don't want users to create a fourth topic at the root level.

My understanding is that the three root topics should be containers but somehow, it doesn't work.

When creating a new topic in Books container, I am getting the following error:

The item Books is a forum container, not a forum. Select one of the forums below instead.



Are you trying to do this in Backdrop or Drupal? This is a Backdrop CMS forum so we can't help with Drupal issues.

If you are trying to do this in Backdrop CMS, you'll need to explain what modules you're trying to do this with. Is it the forum module or the forum_ng module?

Looks like there are quite a few issues with both:

Do any of those issues match the issue you're facing? You should be able to read those even without a GitHub account.

I don't use either module so wouldn't be able to help, but if you can narrow it down a bit, hopefully someone will be able to help you.

My focus was Forum and not Forum_ng because I consider it should be bug free after so many years in service. When testing, I had a crash. I am nervous how it would be on a site in production. The issue showed in github is closer to this one: but the people talk mainly about terminology and not an actual issue in the forum tree.

I believe it's a bug or a concept badly worded inherited from Drupal but still present today in the current Drupal 10 version.

The following has been tested with forum (not forum_ng)

To reproduce it, create a fresh install with Demo Backdrop.

Install forum module: /admin/modules/install Search for Forum, add to installation queue, install Validate this new module: /admin/modules/list Go to the forum URL: /forum


Here is the issue. There is already a created topic General discussion (url: /forum/1). At this level, anybody can create a new topic. You can get endless topics.

Add new Forum topic: /node/add/forum/0 Forums field is required. The only choice is General discussion.


Note that the url is /node/add/forum/0.  The forum has been correctly selected to the only possible choice General Discussion.

You get an error.



Click again and it now works, but it's /forum/2

The root is /forum there is only General discussion. New Topic is a child of General Discussion.

At root level (url: /forum), it's impossible to create a topic. All new topics are children of General Discussion.

How do you create 3 topics at root level? and only 3 for regular users, only an admin could add a fourth topic.

Here is where container should step in. Create 3 containers and drop General Discussion in one of them.

Add container: /admin/structure/forum/add/container


General Discussion: /forum/1 Container #1: /forum/2

If I try to edit forum General Discussion and move it into Container #1,





I have created 3 containers and dropped General Discussion into Container #1. I want now to create a new topic in Container #3 but I am getting an error: The item Container #3 is a forum container, not a forum.


THAT IS THE BUG. I don't understand the logic behind it like many other folks for so long.

Here is the list of the created terms: /admin/structure/taxonomy/forums/list


Containers and Forums share the same taxonomy terms.

My logic would be: 1/ Create as many forum topics as you wish inside a container. 2/ You can create as many containers as you wish but it is usually an admin or an editor privilege. 3/ You can't create a container inside a forum.

It's close to the mentioned link above where the author talk about the same concept.


Someone suggested in a old Drupal forum post (Drupal 5 or 6) to differentiate the terms between Container and Forum in the taxonomy. I am clueless how to solve this issue. Thanks for your interest into this matter.

Root Forum Topics must done with taxonomy.

To delegate the forum admin to others users, without using Forum Access module, the following permissions were given:

It only works if Administer comments are also granted to the forum admins, giving at the same time to many permissions (like editing other users comments)

Doing so and using Forum module, I encountered a couple time a fatal bug:

Uninstalling the Forum module doesn't fix the issue. The process doesn't drop all involved Forum tables from the database. When re-installing the Forum module, the system warns that Forum tables already exist.

I tried afterwards Forum NG module but its incompatible with a previous Forum module installation already uninstalled.

With a new BackDrop fresh install, Forum NG module works fine. Unfortunately, Forum Access module is not for Forum NG module. When installing it, it installs Forum module too as required module.

My final comment at this moment would be avoiding using Forum module, too prone to a system crash.