Yes, I've had the exact same problem in the past.
It is caused by Compiz being enabled by default on Hardy Heron.
Compiz gives you all the cool effects, such as Wobbly Windows etc.
There is an entry in Tips and Tricks about it. Basically....
"If you start Steam under Crossover Games 7.1 on Ubuntu 8.04 Hardy Heron and find that the Steam GUI won't take focus, there is an easy way to resolve the issue.
Taking focus, as in you can see the steam tray icon in the gnome tray panel and the task shows up in the gnome task panel, but the steam interface doesn't appear on the screen.
Hardy Heron comes with Compiz configured out of the box. You need to disable it.
This site contains details on how to disable compiz and how to setup a desktop icon to enable and disable compiz on the fly.
http://www.ubuntu1501.com/2008/04/stop-compiz-fusion-from-loading.html"
That should sort you out :)
Ubuntu 8.04, AMD64X2 5200+, 7900GS, latest version of CrossOver.
When i start up steam I get the system tray icon, and that menu
works. However I can see for example the steam update page, main
page, friends etc. are open, according to my workplace viewer, but I
can't see them or interact with them. Also notifications pop up on
the side very delayed, but if I click I can start a conversation
window (though I cant see text, and the window is semi-transparent).
Anyone else experiencing something similar?