I have had no luck with the in-game Steam UI. I've had to turn it off or it would crash the game every time it wanted to give me an alert pop-up or some one wanted to chat with me.
There is also an issues I have had for several version now in the Steam GUI of the scrolling acting weird. I can scroll down a page, but as soon as I move the mouse, it jumps back to the top of the page.
let me know if there is a solution or if it is a known issue.