I generally like the transition happening between the user list and the login form, but there are some minor details resulting in the transition feeling less fluid and "jumpy". Doing my best to identify them, but I'm not sure I am doing the best job describing this:

- The first part is right. all elements fade out, while the avatar says in place. If the selected item is not the first, there is an extra transition, moving the item to the 0 position while fading out the rest.
- In the next phase there's a couple of things that I don't think work very well. The avatar seems to slide horizontally when the form elements appear. Would be nice to try to avoid that. The next one is tricky to describe. Maybe it's the easing, but maybe just layout issue. Before reaching the final position, the elements seem to overshoot (buttons at the bottom go lower in Y, avatar and label+entry go higher and then return (similar to easeOutBack in jquery). The jump doesn't feel right.