I'm having problems when I open a new window from the page where I have a collapsible panel.
I use this piece of code for opening the window:

Response.Write("<script language = \"Javascript\">var win=window.open('grid.aspx',null,'width=620,height=460,top=70,left=100','true');</script>");

When I close that window, my I find my collapsible panel in expanded state (no matter if I expanded it or not) and the worst thing is that I can't collapse it any more. It just flickers and that's it.
The panel works fine before opening the new window.
Does anyone have the idea what causes this?

No idea, but somehow this is interfering with the ScriptManager hookup of the Atlas components.  Could you just launch your new page from script instead of injecting it from the serverside?  Meaning, can you just put that code in the "OnClientClick" property of a button or something rather than doing it from a postback?

I don't know how to do it at this moment because I use session object for storing parameter values and showing the results in a new window. I have a basic page where the user defines his search criterias (there can be several criterias) and I need to show results on the next page based on these criterias. I don't know any way to collect parameter values and show them avoididing  a postback....and I'm not very familiar with javascript. Hope you understand my situation. Do you have any ideas?

I have run into a similar issue when I load a UserControl from the serverside during an AJAX callback.  Did you ever discover a workaround for this issue?