How to set to show `Select a category...` when user create a new topic

I am a new admin of our discourse forum, and i have created some categories, but i do NOT want to show a default category when user create a topic, i want show user Select a category... instead, like the following pic shows. any one know how to set this?

thanks a lot for helping.

「いいね!」 1

That’s the default behavior if you disable allow uncategorized topics on Site Settings.

Unless the user click on the + New Topic while on viewing a specific category, because that will be pre-selected for him.

「いいね!」 3

solved, thanks for help.