I've got an ASPX page which stores a value in Session.  A button on that same page fires javascript which is a 'window.open' call.  The second window opens, but in the codebehind of the 2nd page, Session is gone.  I've run Fiddler to see what the Session cookie ID is, and it's exactly the same as was in the first window.

Has anyone else experienced this?

I tried in IE and Firefox, and it happens in both browsers.

Saw the root cause mentioned in a few places.  The reason is that the window is sometimes created in the wrong IE process, thus losing its session.  If using authentication, it will also prompt you for credentials even though you are already authenticated in the first browser.   

See http://kbalertz.com/196383/Windows-Opened-Script-Authentication-Session.aspx for more details.  As for firefox, no idea.

~Rick

 EnableSessionState="false" was my downfall there.  Makes sense that session would be null, right? ;)

 Thanks.