How to extend only a single forum of a category?
Forums inherit their top parent (category) layout. Thus if you need to change some forum layout you should change its top parent Category layout. Child forums’ layout depends on the top category (blue panels) layout. They cannot have a different layout.
In case you want to say thank you !)
We'd really appreciate and be thankful if you leave a good review on plugin page. This is the best way to say thank you to this project and support team.
@sofy But your troubleshooting forum is extended without an arrow, while the other forums in the same category are collapsed. How did you do that?