AnatolyR:
Here is an Infragistics blog posting claiming 6.2 will work with Atlas:
http://blogs.infragistics.com/blogs/tony_lombardo/archive/2006/05/08/174.aspx
However, in reality, I find that 6.2 doesn't work with Atlas. I tried some Infragistics controls with the Atlas April CTP and that didn't work. I've tested more against the Atlas June CTP and still have problems.
I've had problems using the WebTab, WebCombo, and WebGrid with UpdatePanel. In some cases, I've had a completely functioning page with an UpdatePanel and just adding an Infragistics control to the page (and doing nothing else) caused it to break.
I sent Infragistics test projects showing things that are broken and they filed them as bugs. I just don't know how long it will take to get the problems fixed--especially since their development team won't be able to "review and assess" the situation for a week. As we need to move forward on our project, I'm investigating a couple of options:
1) Don't use Atlas and use some of the Infragistics controls' javascript functionality to do what we need. We could end up writing a lot more javascript than we want to, though.
2) Use telerik's r.a.d. controls instead if they work properly with Atlas (as they claim to be the first control library compatible with Atlas).