The owner or an admin can close the door using the door button next to Invite, or Close the Door in Room Settings.
What changes when the door is closed?
Members knock as well as guests. The owner and admins can still walk in. People already inside stay in the room.
Answering a knock
Anyone inside who is not a guest can let someone in as a guest or member. Choose based on whether you want them to help decorate. The × dismisses the knock and tells the person they were not let in.
If someone leaves before you answer, their knock may stay marked as left. Letting them in still allows them to return within 15 minutes.
If someone is causing trouble, see managing people in a room.