Should be able to specify public/private room (preset?) when creating a room

[Half-Shot]

When creating a room, I forget nearly everytime to make the room publically joinable. I usually share around the alias before looking rather stupid when nobody can join.

For the sake of stupid, the option to be able to set a room public or private in the create room dialog would be helpful, ideally requiring you to select an option to continue.

[turt2live]

Related: https://github.com/vector-im/riot-web/issues/5599

[lampholder]

Since the redesign has moved the 'create room/start chat' UX to a (+) next to the roomlist header, there's a chance we could pick some very sensible defaults depending on whether somebody is trying to create a 1:1, room, or 'group'.

But yes, I'd like to see this decision somehow incorporated into our create room flow.

[Half-Shot]

Gorgeous, this is done.