MyBB Community Forums

I have set the users' permission by group.
I specified that the groups can't delete any post.
I configured also in each forum the permission, and i set to copy the permission to standard configuration.

I see the logs, and the users still delete the posts.

I tried to edit the permissions for each group in the forum permission panel... there is the stick to the delete post option.
I de-stick it, and save.
When i turn to view if the option are de-sticked, it still sticked.

How can i solve this?

You have to tick the "Use custom permissions (below)" option when setting the permissions for any of those settings to take effect.