Right now when joining a channel via /join command a banner is shown (but never disappears) that says "Joining room #room:network." I think it would be better to show a full page in the chat history area showing this message with the infinite scroll bar. As far as I understand there's no real definable progress to joining a room, just a waiting period while it gathers the events. So a regular progress bar wouldn't suit but the infinite loading bar would. Just my 5c (2c pieces have been discontinued).
Not sure about the infinite progress bar, but we should make sure the banner disappears after joining the room
The banner now disappears when the room is joined and then it's switched to which I think fulfills what we want to achieve from this so closing