There's a difference between a new beta and an app that has been in closed beta for months already and only today has been made available to the public. Just because it's 'beta' doesn't mean there should be obvious trivial bugs present.
Just to run off a few issues we found within literally minutes of using the app:
1. Resizing window to a small size then making it large again causes the entire chat view to become very narrow.
2. Messages sent by one user, often get displayed next to another person's username (so it looks like someone else wrote the message).
3. Notification popups appears even when the app is actively being viewed.
4. If you go away from keyboard, the app sets you as idle, but when you return, the idle indicator doesn't get removed
++ on the notifications. my biggest beef with hipchat is it will send emails of conversations as i am having the conversations. email notifications when I am away is nice, kind of annoying when you are actively typing in the window.
