Help!! Creating a thread

It depends on which sub-forum you are on.

For instance, in the Buy/Sell/Trade forums, you must choose at least one prefix. Same with the News section.

You can choose more than one prefix also in some places - that's via an addon which is appropriately called "Multi-prefix".

But in the general forum area, there's no prefix requirement.

I think what you're referring to is a change in the way the addon works somewhere along the line. I believe there used to be an option called "no prefix" when you are on mobile and scrolling through the list, and if you selected that, it cleared the other ones you had selected, is that what you're referring to?

I believe that created a conflict in functionality with certain phones or something, so instead he changed it to a checklist. So if you choose one, and want to undo it, you just uncheck it. If this doesn't describe what you're seeing, let me know what device you're using, that might make a difference. I checked my iPhone but I don't have an Android

Remember though that for forums like BST & news, you can't post a thread without a prefix. That's just a choice I made when setting things up, it's not like that is locked in stone but it makes sense in certain areas.